GB2373855A - Determining chemical oxygen demand - Google Patents
Determining chemical oxygen demand Download PDFInfo
- Publication number
- GB2373855A GB2373855A GB0107869A GB0107869A GB2373855A GB 2373855 A GB2373855 A GB 2373855A GB 0107869 A GB0107869 A GB 0107869A GB 0107869 A GB0107869 A GB 0107869A GB 2373855 A GB2373855 A GB 2373855A
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- Prior art keywords
- cod
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- color
- glucose
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 44
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 44
- 239000001301 oxygen Substances 0.000 title claims abstract description 44
- 239000000126 substance Substances 0.000 title claims abstract description 38
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 claims abstract description 594
- 239000008103 glucose Substances 0.000 claims abstract description 594
- 238000000034 method Methods 0.000 claims abstract description 299
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 177
- 239000003153 chemical reaction reagent Substances 0.000 claims abstract description 113
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 claims abstract description 48
- DOBUSJIVSSJEDA-UHFFFAOYSA-L 1,3-dioxa-2$l^{6}-thia-4-mercuracyclobutane 2,2-dioxide Chemical compound [Hg+2].[O-]S([O-])(=O)=O DOBUSJIVSSJEDA-UHFFFAOYSA-L 0.000 claims abstract description 20
- YUVLVONHNMXKBW-UHFFFAOYSA-L [Ag+2].OS(O)(=O)=O.[O-]S([O-])(=O)=O Chemical compound [Ag+2].OS(O)(=O)=O.[O-]S([O-])(=O)=O YUVLVONHNMXKBW-UHFFFAOYSA-L 0.000 claims abstract description 18
- 239000000523 sample Substances 0.000 claims description 653
- 239000011541 reaction mixture Substances 0.000 claims description 403
- 238000012360 testing method Methods 0.000 claims description 167
- 239000000243 solution Substances 0.000 claims description 161
- 238000010790 dilution Methods 0.000 claims description 94
- 239000012895 dilution Substances 0.000 claims description 94
- 229910000372 mercury(II) sulfate Inorganic materials 0.000 claims description 92
- 239000000203 mixture Substances 0.000 claims description 88
- 238000006243 chemical reaction Methods 0.000 claims description 85
- 239000012153 distilled water Substances 0.000 claims description 80
- 238000011534 incubation Methods 0.000 claims description 69
- 239000002002 slurry Substances 0.000 claims description 40
- 239000002699 waste material Substances 0.000 claims description 36
- 239000012470 diluted sample Substances 0.000 claims description 23
- 238000002156 mixing Methods 0.000 claims description 19
- 229940074994 mercuric sulfate Drugs 0.000 claims description 16
- 239000007787 solid Substances 0.000 claims description 11
- 239000012086 standard solution Substances 0.000 claims description 11
- 229910000367 silver sulfate Inorganic materials 0.000 claims description 10
- 239000003086 colorant Substances 0.000 claims description 9
- 238000007865 diluting Methods 0.000 claims description 9
- 230000003287 optical effect Effects 0.000 claims description 9
- FGUUSXIOTUKUDN-IBGZPJMESA-N C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 Chemical compound C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 FGUUSXIOTUKUDN-IBGZPJMESA-N 0.000 claims description 8
- 101150114843 Mgll gene Proteins 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 5
- 238000006418 Brown reaction Methods 0.000 claims description 4
- 238000012937 correction Methods 0.000 claims description 4
- 235000013305 food Nutrition 0.000 claims description 4
- 239000011521 glass Substances 0.000 claims description 4
- 239000012488 sample solution Substances 0.000 claims description 4
- 239000002154 agricultural waste Substances 0.000 claims description 3
- 239000010828 animal waste Substances 0.000 claims description 3
- 235000013361 beverage Nutrition 0.000 claims description 3
- 235000013399 edible fruits Nutrition 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims 1
- 239000008213 purified water Substances 0.000 claims 1
- 239000002351 wastewater Substances 0.000 abstract description 16
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid group Chemical class S(O)(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 73
- 235000011149 sulphuric acid Nutrition 0.000 description 70
- JKNZUZCGFROMAZ-UHFFFAOYSA-L [Ag+2].[O-]S([O-])(=O)=O Chemical compound [Ag+2].[O-]S([O-])(=O)=O JKNZUZCGFROMAZ-UHFFFAOYSA-L 0.000 description 65
- 239000011550 stock solution Substances 0.000 description 65
- 241000209140 Triticum Species 0.000 description 58
- 235000021307 Triticum Nutrition 0.000 description 58
- 235000013339 cereals Nutrition 0.000 description 58
- 238000003113 dilution method Methods 0.000 description 50
- 239000012925 reference material Substances 0.000 description 50
- 239000000706 filtrate Substances 0.000 description 38
- 235000013311 vegetables Nutrition 0.000 description 24
- 235000019482 Palm oil Nutrition 0.000 description 22
- 239000002540 palm oil Substances 0.000 description 22
- 238000010561 standard procedure Methods 0.000 description 10
- 239000007800 oxidant agent Substances 0.000 description 8
- 230000005180 public health Effects 0.000 description 8
- 239000005416 organic matter Substances 0.000 description 7
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 6
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 6
- 230000001590 oxidative effect Effects 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000001888 Peptone Substances 0.000 description 4
- 108010080698 Peptones Proteins 0.000 description 4
- 230000029087 digestion Effects 0.000 description 4
- 230000036541 health Effects 0.000 description 4
- 239000003415 peat Substances 0.000 description 4
- 235000019319 peptone Nutrition 0.000 description 4
- 238000010992 reflux Methods 0.000 description 4
- 238000003911 water pollution Methods 0.000 description 4
- 241000283690 Bos taurus Species 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- SOCTUWSJJQCPFX-UHFFFAOYSA-N dichromate(2-) Chemical compound [O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O SOCTUWSJJQCPFX-UHFFFAOYSA-N 0.000 description 3
- ZPWVASYFFYYZEW-UHFFFAOYSA-L dipotassium hydrogen phosphate Chemical compound [K+].[K+].OP([O-])([O-])=O ZPWVASYFFYYZEW-UHFFFAOYSA-L 0.000 description 3
- 210000003608 fece Anatomy 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 229910052938 sodium sulfate Inorganic materials 0.000 description 3
- 235000011152 sodium sulphate Nutrition 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000005352 clarification Methods 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 229910000396 dipotassium phosphate Inorganic materials 0.000 description 2
- 235000019797 dipotassium phosphate Nutrition 0.000 description 2
- 239000003925 fat Substances 0.000 description 2
- IMBKASBLAKCLEM-UHFFFAOYSA-L ferrous ammonium sulfate (anhydrous) Chemical compound [NH4+].[NH4+].[Fe+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O IMBKASBLAKCLEM-UHFFFAOYSA-L 0.000 description 2
- 239000010842 industrial wastewater Substances 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 239000010841 municipal wastewater Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 150000002894 organic compounds Chemical class 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- YPNVIBVEFVRZPJ-UHFFFAOYSA-L silver sulfate Chemical compound [Ag+].[Ag+].[O-]S([O-])(=O)=O YPNVIBVEFVRZPJ-UHFFFAOYSA-L 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 239000001117 sulphuric acid Substances 0.000 description 2
- 238000004448 titration Methods 0.000 description 2
- 241000251468 Actinopterygii Species 0.000 description 1
- 241000228245 Aspergillus niger Species 0.000 description 1
- 244000063299 Bacillus subtilis Species 0.000 description 1
- 235000014469 Bacillus subtilis Nutrition 0.000 description 1
- 241000894006 Bacteria Species 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- YZCKVEUIGOORGS-OUBTZVSYSA-N Deuterium Chemical compound [2H] YZCKVEUIGOORGS-OUBTZVSYSA-N 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- 241000233805 Phoenix Species 0.000 description 1
- 238000002835 absorbance Methods 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 231100000209 biodegradability test Toxicity 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 229910052805 deuterium Inorganic materials 0.000 description 1
- 239000010840 domestic wastewater Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004710 electron pair approximation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 235000019198 oils Nutrition 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007430 reference method Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 238000012421 spiking Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000013026 undiluted sample Substances 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/18—Water
- G01N33/1806—Biological oxygen demand [BOD] or chemical oxygen demand [COD]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/10—Composition for standardization, calibration, simulation, stabilization, preparation or preservation; processes of use in preparation for chemical testing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/14—Heterocyclic carbon compound [i.e., O, S, N, Se, Te, as only ring hetero atom]
- Y10T436/142222—Hetero-O [e.g., ascorbic acid, etc.]
- Y10T436/143333—Saccharide [e.g., DNA, etc.]
- Y10T436/144444—Glucose
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/20—Oxygen containing
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- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Analytical Chemistry (AREA)
- Molecular Biology (AREA)
- Biomedical Technology (AREA)
- Biodiversity & Conservation Biology (AREA)
- Medicinal Chemistry (AREA)
- Physics & Mathematics (AREA)
- Emergency Medicine (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
- Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
Abstract
Chemical oxygen demand (COD) of water or waste water is determined using colour charts or reference tables obtained using (a) standard glucose solutions and (b) mercuric sulphate, (c) potassium dichromate and (d) sulphuric acid - silver sulphate reagents. Also claimed is a kit for determining COD comprising reagents (a), (b), (c) and (d) plus a photometer and the charts or reference tables and methods of determining COD in effluents using reagents (a) to (d) and the charts or tables.
Description
A rapid method for estimation of Chemical Oxygen Demand.
Field of the Invention
The present invention relates to a rapid method for estimation of Chemical Oxygen
Demand (COD) of water and wastewater. It particularly relates to determination of
COD. of industrial waste or domestic waste water or for determining the degree of pollution or develop designs for effluent treatment plants or efficiency of treatment plants or quick, rapid and onsite estimation of COD of water and wastewater or in untreated municipal wastewater or activation and pre-clarification tank inlets or cooling water and storm water reservoirs.
Background and prior art references
Oxygen demand is a significant parameter for determining the effect of organic polluants in water. As microorganisms in the environment ingest the organic material, oxygen is depleted. This in turn can be harmful to fish and plant life.
(http ://www. spectronic. com/spectron/spctech2. htm). Wastewater from food processing is non-toxic but organic. High concentration of nutrients can be harmful for the environment. Extra quantities of nitrogen, fat and phosphorus require more oxygen for bacteria to decompose. If Chemical Oxygen Demand (COD)/
Biochemical oxygen demand (B. O. D) content of the water is excessive, the oxygen supply in the water may be depleted below the level required to sustain aquatic life.
(Ref: http ://tnfo. rf) sk. is/verkefni/1077/hfe 4f2. htm).
The Chemical Oxygen Demand (COD) determination is a measure of the oxygen equivalent of that portion of the organic matter in a sample that is susceptible to oxidation by a strong chemical oxidant under controlled conditions (American Public
Health Association (APHA). (1998). In Standard methods for examination of water and wastewater. 20 Edn. American Public Health Association (APHA), American
Water Works Association (AWWA), Water Pollution Control Federation (WPCF),
Washington, DC).
The limitation of the test lies in its inability to differentiate between the biologically oxidizable and biologically inert material. COD determination has an advantage over
BOD test in that the results can be obtained in less than five hours where as BOD requires 3 to 5 days. Further the test is relatively easy and with not much interference. (American Public Health Association (APHA), 1976). In : Standard methods for examination of water and wastewater. 14th edn American Public Health
Association (APHA), American Water Works Association (AWWA), Water Pollution
Control Federation (WPCF), Washington, DC).
The main chemical compounds in wastewater are Chemical Oxygen Demand (COD), nitrogen, phosphorus, fats, oils and grease. COD and BOD5 are important parameters for measurement of organic matter content and oxygen needed to decompose the organic compounds. During the decomposition of organic matter there is less oxygen available in the sea and no oxygen in some places. It is possible to calculate COD or BOD into standard personal units, 60 g of oxygen to decompose the organic compounds from one person per day or equaling of 135 g of oxygen to decompose Chemical Oxygen Demand (COD) in waste water (COD= 2.25 x BOD). (Ref: http://info. rfisk. is/ verkefni/1077/hfe4f2. htm).
The calorimetric dichromate reflux method is commonly used method for determining the Chemical Oxygen Demand (COD) content in a sample, and has been preferred over procedures using other oxidants because of superior oxidizing ability, applicability to a wide variety of samples and ease of manipulation (American
Public Health Association (APHA). (1989). In : Standard methods for examination of water and wastewater. 17th edn. American Public Health Association (APHA),
American Water Works Association (AWWA), Water Pollution Control Federation (WPCF), Washington, DC). The basic principle involved is oxidizing the most types of organic matters by a boiling mixture of chromic and sulfuric acids. A sample is refluxed in strongly acid solution with a known excess of potassium dichromate (K2Cr207). After digestion, the remaining unreduced K2Cr207 is titrated with ferrous ammonium sulfate to determine the amount of K2Cr207 consumed and the oxidizable organic matter is calculated in terms of oxygen equivalent.
The determination of Chemical Oxygen Demand (COD) is widely used in municipal and industrial laboratories to measure the general level of organic contamination in waste water (Ref: http : //www. chemetrics. com/lnstProd/COD. I. htm).
Wide ranges of instruments are available for Chemical Oxygen Demand (COD) estimation. CHEMetrics'-employs EPA (Environmental Protection Agency, USA) approved Dichromate reactor digestion method. (http : //www. chemetrics. com/lnstProd/COD.l. htm). Spectronic Instruments provide SPECTRONICR Spectrophotometer and the Bioscience ACCU-Test system based on APHA method. (American Public Health Association (APHA). (1989). In :
Standard methods for examination of water and wastewater. 17th edn American
Public Health Association (APHA), American Water Works Association (AWWA),
Water Pollution Control Federation (WPCF), Washington, DC). It uses a semi-micro conversion of the Standard Methods procedure for the determination of Chemical Oxygen Demand (COD). (Ref: http : //www. spectronic. com/spectron/ spctech2. htm).
In the North Dakota Department of Health (NDDH), Chemistry Division Chemical Oxygen Demand (COD) SOP (Ref: http : //www. health. state. nd. us/lab/ METHODS/I- 1-4. HTM) COD determination is through comparison of absorbance for the standards and the samples in HACH COD reactor and Sequonic Turner model 390
Spectrophotometer.
ISCO-STP COD analyzers and the Phoenix analyzer uses ozone for rapid oxidation and provides continuous Chemical Oxygen Demand (COD) measurement
corresponding directly to result of the laboratory standard dichromate method.
(http ://www. isco/htmi/ prdprCOD. html).
Among the reference methods of Chemical Oxygen Demand (COD) determination, EPA method 410. 1/ 410. 2 and the Standard Method SM5220-D employ closed refluxing (Ref : http :// splash. metrokc. gov/wir/envlab/LABGUIDE/ comref. htm). The biodegradability test - 5-day and 28 day includes COD 5 and 15 day determinations in the reference OCED method 3101D--SOQ Appendix B Methods used by Burlington Research, Inc. (Ref: http ://199. 72.5. 39/sogapb. htm).
PASTEL UV (R) system works exclusively in UV range of light spectrum with UV analyzer (Spectrophotometer). It requires 16 photodiodes and specially developed pulsed deuterium lamp. This analyzer requires calibration for accuracy within a very specific sample category such as industrial wastewater. For each additional application a new base line spectra has to be customized for specific samples. In this method the co-relation is only for BOD and TSS (Total Suspended Solids) which is 90% when compared to the traditional test methods. For COD the co-relation is valid only upto 6000 mg/L COD only. It is a indirect estimation based on reference data stored in internal UV based software (Ref.: http : //www. azurenv. com/ispec. htm).
The major limitations in different cases are the economics of the methods used, instruments employed and the time consumed. CHEMetrics'uses a standard digester block for heating the sample for 2 h at 150oC. In addition, the method needs to employ a Chemical Oxygen Demand (COD) Photometer (A-1051C) or
Spectrophotometer which accepts a 16 mm diameter cell. The major limitation is that the results are not reportable to USEPA. On the other hand, 13 mm cells can be read in CHEMetrics WR and A1051 photometer. However, the results are good for monitoring purposes only.
BioScience's EPA Accepted ACCU- TESTR method needs specific type of Chemical
Oxygen Demand (COD) reagent vials, a heating block, data management software package, etc. are required. It makes each test quite costly. BioScience's EPA
Accepted ACCU-TEST is avaitabte on) y in a medium sensitivity ranges for
Spectrophotometry 5 to 4500 mg/L Chemical Oxygen Demand (COD). In order to use the BioScience COD vials in the SPECTRONICR 401, both the test tube holder and the Light shield are required where as the GENESYS 2 or GENESYS 5 require the cell holder Platform and its Test tube holder (Ref: http : //www. spectronic. com/spectron/spctech2. htm).
In the North Dakota Department of Health (NDDH) Chemistry Division Chemical Oxygen Demand (COD. ) SOP (Ref: http://www. health. state. nd. us/lab/METHODS/I- 1-4. HTM) Chemical Oxygen Demand (COD) determination is in a narrow range of 0 to 150 and 150 to 1500 mg/L. The calorimetrically determined Chemical Oxygen
Demand (COD) value is based on measuring the consumed oxidant in the chrome (cor6) and chromous (cor3) valence state. The method employs HACH COD reactor and Sequonic Turner model 390 Spectrophotometer. The spiking solutions in the 0 to 150 mg/L range are 10,25, 50 and 150 where as for 150 to 1500 mg/L ranges, 5 concentration ranges 100,250, 500,1000 and 1500) are employed. It needs a sample volume of 10 ml, in addition to heating for 2 hours at 150oC.
In the Manganese III method for Chemical Oxygen Demand (COD) analysis (U. S. Patent document 5,556, 787 Sept. , 1996) determination is done by using an analysis reagent comprised of a mixture of stabilized Manganese III ion and an inorganic non-oxidizing acid such as sulfuric or phosphoric acid. The method involves titration and calorimetric determination. The method involves digestion of the test sample by heating between 100 to 200OC for up to 2 hours.
A method based on redox cell involved treatment of organic carbon with an excess of an oxidizing agent. The remaining oxidizing agent is determined in a redox cell to ascertain how much of the oxidizing agent was consumed by the organic carbon.
This was the COD. This is multi-step process involving a large number of reagents (U. S. Patent 3,930, 798 Jan. , 1976). Another redox based method involves ozone as an oxidizing agent (U. S. Patent 5,324, 666 Jun. , 1994). The accuracy of the process is limited only by the control range of the ozone generating pumps. It can work within a range of less than 0.5 ozone load i. e. the ratio of chemical oxygen demand to added ozone. By increasing the ozone input the measuring range may be extended upwards but with reduced accuracy.
All the methods employed so far have long refluxing or digestion periods and are followed by titration or spectrophotometric reading of the standards and the samples at different wavelengths.
In the present invention the major limitations involved in estimation of chemical oxygen demand of water and wastewater have been over come. The novelty of the present invention is in use of a rapid, simple and effective method for estimation of
COD of a wide range of samples. Another novelty of the present invention is the reduction in time period taken for estimation of COD, from 2h to less than 5 minutes.
In the present invention, parameters have been studied for preparation of a reaction mixture, which is easy to handle. Another novelty of the present invention is in the use of very small quantities of reagents and the test sample. In the present invention the various reaction mixtures can be read instantly for a very wide range of COD loads by using minor equipment e. g. photometer. Another novelty of the present invention is the ability to conduct the estimation on site, avoiding any possible changes in the test sample quality. Yet another novelty of the present invention is the COD color chart is used for determination of COD. over a wide range. Another novelty of the present invention is the flexibility to use reagents for determination of
COD. over a wide range. Another novelty of the present invention is the simplicity for preparing reference standards easily and rapidly. Another novelty of the present invention is the stability of color based reference standards for long period without preserving them at low temperatures. These can thus be used repeatedly.
OBJECTS OF THE INVENTION
The main object of present invention is to provide a rapid method for estimation of
Chemical Oxygen Demand (COD) of water and wastewater, which obviates the drawbacks listed above.
Another object of the present invention is to provide a cheap and simple method for quick estimation of COD of water and wastewater.
Yet, another object of present invention is to provide a rapid and sensitive method which, capable of determining COD in small quantities of test sample.
Yet another object of the present invention is to provide a color chart over a wide range of COD values.
Yet, another object of the present invention is to provide a kit for COD. estimation.
Yet, another object of the present invention is to provide a method which does not require much technical skill and sophisticated equipment.
Another object of the present invention is to provide an effective process for COD estimation with very little loss of sample.
SUMMARY OF THE INVENTION
The present invention has solved the problem of longer duration and consumption of large quantities of chemicals in COD estimation. The method of the invention has removed the need for heating the reaction mixture for nearly 2 h at 148OC, which is conventionally employed by standard methods and other commercially available kits.
One mL of sample solution is mixed with three reagents, consisting of 0.02 g mercuric sulphate, 0.5 mL of 0.25 N potassium dichromate solution and 1.5 mL of sulphuric acid-silver sulphate in a sequential manner. Its COD is checked with the help of color chart. Sample (s) showing a COD value of more than 10000 mg/L are diluted. After establishing its approximate COD value, the sample is diluted further, if necessary, to achieve a COD value in the range of 300 to 500 mg/L. Reagents listed above are added to these diluted sample and read its OD at 585 and 635 nm. These
OD values are used for calculating precise COD values by comparing it with standard glucose solution.
The main utility of the present invention is for determining the degree of pollution, to develop designs for effluent treatment plants and to determine efficiency of treatment plants. Monitoring of COD is important for design and operation of wastewater treatment equipment. Another utility of the present invention is to provide an efficient method for quick, rapid and onsite estimation of COD of water and wastewater. Other utilities include applications in untreated municipal wastewater, activation and pre-clarification tank inlets, and even cooling water and storm water reservoirs. It is also used as a standard parameter for characterization of wastewater loads or for proof of a required purification level.
DETAILED DESCRIPTION OF THE INVENTION
The chemical oxygen demand (COD) determines the amount of oxygen required for chemical oxidation of organic matter using a strong chemical oxidant such as potassium dichromate under reflux conditions. The test is widely used to determine: 1) The degree of pollution in water bodies and their self purification capacity, 2)
Efficiency of treatment plants, 3) Pollution loads, 4) Provides rough idea of B. O. D, which can be used for B. O. D estimation. The conventional estimation is based on the principle that most of the organic matter is destroyed when boiled with a mixture of potassium dichromate and H2SO4 producing C02 and H20. A sample is reflexed with a known amount of potassium dichromate. It is then titrated against ferrous ammonium sulphate. The amount is proportional to O2 required to oxidize the organic matter. The method takes 2 to 3 hours. Using standard COD kits available in the market can also do COD estimations. The standard COD kit method involves the use of thermoreactor and a photometer can also take 2 to 3 hours to complete.
Since the initial COD of the sample cannot be guessed, kits for different COD ranges have to be tried and even sample may still has to be diluted. Dilution of sample leads to further use of more kits, it thus makes the estimation more expensive. However, a technique has been devised here, which gives good estimate of COD within 5 to 10 min and consumes very small quantities of reagents compared to conventional standard methods. It can be carried out easily on site. The reaction mixture develops a color, which can be easily read and distinguished. In the first stage, a sample is added without any dilution. The color developed with the undiluted sample gives a direct estimate of COD or gives a clear indication of the extent to which a sample needs to be diluted before adding to the reaction mixture. For samples with COD value of more than 10000, the color of the sample and the different reagents will be
C10000 (brown). Make 4 different dilutions of the sample i. e. 10, 100, 200 and 500.
The various diluted samples can be tested in increasing order of their dilution. Once a diluted sample and the reagent mixture show a color between C100 (yellow) and
C500 (sea green). This dilution can be 10 to 300 times, depending upon the initial
COD of the sample.
Accordingly, the present invention provides a rapid method for semi-quantitative estimation of Chemical Oxygen Demand (COD), which comprises: i) preparing standard solutions by dissolving glucose in water, ii) mixing the standard solutions with different reagents, mercuric sulphate (HgS04), potassium dichromate (K2Cr207) and sulphuric acid (H2SO4) silver sulphate reagent in a sequential manner. iii) mixing the sample with different reagents, mercuric sulphate (HgS04), potassium dichromate (K2Cr207) and sulphuric acid (H2SO4) silver sulphate reagent in a sequential manner. iv) diluting the sample to a desired level and adding the reagents in a sequential manner. v) noting down the color of the reaction mixture visually and record the color code using a color chart within 1 minute of incubation and reading optical density (O. D.) of the sample.
Accordingly the present invention provides a method for the preparation of COD chart useful for the estimation of COD in a sample, said method comprising the steps of: a) preparing standard glucose solution by dissolving glucose in distilled water at a concentration ranging between 200 mg/L to 1, 00,000 mg/L with a COD concentration ranging between 213 mg/L to 1,06, 700 mg/L, b) mixing 1 mL of standard glucose solutions from step (a), individually, with three reagents, consisting of 0.02 g mercuric sulfate, 0.5 mL of 0.25 N potassium dichromate solution and 1.5 mL of sulfuric acid-silver sulfate in a sequential manner, and c) preparing a COD color chart of different glucose concentration as shown in figure 1 of accompanying drawings based on the COD concentration ranging between 213 mg/L to 1,06, 700 mg/L, and which chart is useful for rough estimation of COD values by comparing the colors of the chart with the color of the samples.
The present invention also provides a rapid method for the estimation of COD of an effluent from domestic, industrial, municipal and other sources, said method comprising the steps of a) preparing a set of standard glucose solutions by dissolving glucose in distilled water at a concentration ranging between 300 mg/L to 500 mg/L, with a COD concentration of 320 mg/L to 535 mg/L, b) mixing 1 mL of standard glucose solutions from step (a), individually, with three reagents, consisting of 0.02 g mercuric sulfate, 0.5 mL of 0.25 N potassium dichromate solution and 1.5 mL of sulfuric acid-silver sulfate in a sequential manner, c) mixing 1 mL of a sample to be tested with 0.02 g mercuric sulfate, 0.5 mL of
0.25 N potassium dichromate and 1.5 mL of sulfuric acid-silver sulfate reagents in a sequential manner and noting down the color and if the color of the reaction mixture turns (color code C10000) brown, d) diluting the sample according to table 1 (a) with distilled water till a particular color range of C100 to C10000 is achieved as shown in Figure 1 of accompanying drawing, e) further diluting the sample with distilled water to obtain a COD range in between 320 to 535 mg/L wherein the dilution is determined according to tables 1 (a) & (b), f) mixing 1 mL of diluted sample from step (e), individually, with three reagents, consisting of 0.02 g mercuric sulfate, 0.5 mL of 0.25 N potassium dichromate solution and 1.5 mL of sulfuric acid-silver sulfate in the above sequential manner, g) matching the color of the reaction mixture of the above sample (step f) with the COD color chart provided in Figure 1 of the accompanying drawing, h) noting the optical density (OD) of the reaction mixture of standard glucose solutions (step b) and sample (step f) at 585 nm or 635 nm, against air, i) drawing a correlation between the OD values of above sample with OD values of standard glucose solutions, j) multiplying the OD value of sample (step h) with a correction factor of 1.2, comparing this value (A) with the OD value of standard glucose solution of
COD value 320 to 535 mg/l, k) multiplying value (A) with the compared COD value of standard Glucose solution and divided by the respective OD value of the glucose standard (B), and
1) then multiply value (B) with a dilution factor (in case of diluted sample) to obtain the COD value of the sample in terms of mg/l.
In yet another embodiment, the tables 1 (a) and 1 (b) are as follows :
Table 1 (a)
Color of the Required dilution Color code Expected COD of unknown reaction of sample sample (mg/L) mixture C 10000 10 C1000 10000 C 10000 100C100-C500 10000-50000 C 10000'200C250-C50050000-100000 C 10000 500 C200-C2000 100000-1000000 Table 1 (b) Color of the reaction Expected COD Dilution required to bring COD mixture (mg/L) value (300-500 mg/L) C9000 9000-9500 18-31 C60006000-850012-28 C2000 2000-5500 4-18 C1500 1500-1900 3-6 C1200 1200-1400 2-5 C600 600-1100 2-4 C500 500-550 NIL C400 400-450 NIL C300 300-350 NIL C200 200-250 NIL C150 100-150 NIL C10000-100'N) L In yet another embodiment, in step (d) the dilution of samples, provide dark brown reaction mixture, falling in the range of 10 to 500 for approximate cod values of 10000 mg/l and above as given in Table1 (c) and further dilution of nil to 31 is done to bring the COD in the range of 300 to 500 mg/l as given in Table 1 (d).
In yet another embodiment, in step (e), the samples provide yellowish to blackish brown colored reaction mixture falling in the range of 100 to 9500 mgll COD and the samples are further diluted to nil to 31 times to obtain a diluted sample in the COD range of 300 to 500 mg/l, according to the Table 1 (d).
In yet another embodiment, in step (d) the dilution of samples and color groups range from (A) to (G) for approximate COD values lying in the range of 100 to 9500 mg/l as given in table 1 (d)
In yet another embodiment, tables 1 (c) and 1 (d) are shown below.
TABLE 1 (c)
Color of Color code Dilution Color obtained Expected Expected COD of the of the required to on dilution as COD of the unknown sample reaction reaction bring the per the provided reaction (mg/1) mixture mixture as COD values color chart mixture (mg/ !) per the in the range provided of 100chart1000 mg/) i) 10 C 1000 1000 10000 Dark C 10000 to ii) 100 C 100-C500 100 to 500 10000 to 50000 brown C 100000 iii) 200 C 250-C 500 250 to 500 50000 to 100000 iv) 500 C 200 to C 2000 200 to 2000 100000 to 1000000 Table 1 (d)
Color Color of the Color code of the Expected COD Dilution required to bring group reaction reaction mixture as per of the reaction the COD values in the mixture the chart provided mixture range of 300 to 500 mg/ ! A Yellowish C 100 to C 250 1 to 250 Nil B Yellowish C 300 to C 550 300 to 550 i C Greenish blue C 600 to C 1000 600 to 1000 2 to 4 Blue to grayish D C 1500 to C 2500 1500 to 2500 3 to 6 blue E Dirty brown C 3000 to C 5500 3000 to 5500 6 to 18 Cola brown C 6000 to C 8500 6000 to 8500 12 to 28 G Blackish brown C 9000 to 9500 9000 to 9500 18-31 One more embodiment of the invention provides a kit for estimation of Chemical
Oxygen Demand (COD) which comprises: a) reagents A) HgS04 (solid), B) Glucose standard solutions ranging from 300 to 500 mg/L, C). K2Cr207 solution (0. 25 to 0. 3 N), and D) H2SO4- silver sulfate reagent, b) a glass vial, c) a photometric cell, d) a COD color chart as shown in fig 1 of the accompanying drawing and a photometer suitable for wave lengths in the range of 585 to 635 nm.
One more embodiment the present invention a method for the preparation of reference tables 1 (e) and 1 (f) of COD values, useful for the estimation of COD in a sample, said method comprising the steps of: a) preparing standard glucose solution by dissolving glucose in distilled water at a concentration ranging between 200 mg/L to 1,00, 000 mg/L with a COD concentration ranging between 213 mg/L to 1,06, 700 mg/L, b) mixing 1 mL of standard glucose solutions from step (a), individually, with three reagents, consisting of 0.02 g mercuric sulfate, 0.5 mL of 0.25 N potassium dichromate solution and 1.5 mL of sulfuric acid-silver sulfate in a sequential manner, and c) preparing reference tables 1 (e) and 1 (f) for COD values of different glucose concentration based on the COD concentration ranging between 213 mg/L to
1,06, 700 mg/L, and which tables are useful for rough estimation of COD values by comparing the colors indicated in the tables with the color of the samples.
In another embodiment the present invention provides the reference tables 1 (e) and 1 (f) are as shown below.
TABLE 1 (e)
Color of the Dilution required to Expected COD of Expected COD of unknown reaction bring the COD the reaction sample (mgll) mixture values in the range mixture (mg/1) of 100-1000 mall v) 10 1000 10000 vi) 100 100 to 500 10000 to 50000 Dark brown vii) 200 250 to 500 50000 to 100000 viii) 500 200 to 2000 100000 to 1000000 Table 1 (f)
Color Color of the Expected COD of Dilution required to bring the COD group reaction mixture the reaction mixture values in the range of 300 to 500 mg/l A Yellowish 1 to 250 Nil Yellowish 300 to 550 Nil C Greenish blue 600 to 1000 2 to 4 Blue to grayish Blue to grayish D 1500 to 2500 3 to 6 blue E Dirty brown 3000 to 5500 6 to 18 F Cola brown 6000 to 8500 12 to 28 Blackish brown 9000 to 9500 18-31 In another embodiment, the present invention provides a rapid method for the estimation of COD of an effluent from domestic, industrial, municipal and other sources using reference tables as given above, said method comprising the steps of a) preparing a set of standard glucose solutions by dissolving glucose in distilled water at a concentration ranging between 300 mg/L to 500 mg/L, with a COD concentration of 320 mg/L to 535 mg/L, b) mixing 1 mL of standard glucose solutions from step (a), individually, with three reagents, consisting of 0.02 g mercuric sulfate, 0.5 mL of 0.25 N potassium dichromate solution and 1.5 mL of sulfuric acid-silver sulfate in a sequential manner, c) mixing 1 mL of a sample to be tested with 0.02 g mercuric sulfate, 0.5 mL of
0.25 N potassium dichromate and 1.5 mL of sulfuric acid-silver sulfate reagents in a sequential manner and noting down the color till the color of the reaction mixture turns brown, d) diluting the sample as per tables 1 (e) and 1 (f) with distilled water till a particular color range shown in the tables is achieved, e) further diluting the sample with distilled water to obtain a COD range in between 320 to 535 mg/L wherein the dilution is determined according to tables 1 (e) and 1 (f), f) mixing 1 mL of diluted sample from step (e), individually, with three reagents, consisting of 0.02 g mercuric sulfate, 0.5 mL of 0.25 N potassium dichromate solution and 1.5 mL of sulfuric acid-silver sulfate in the above sequential manner, g) matching the color of the reaction mixture of the above sample (step f) with the COD color provided in tables 1 (e) and 1 (f), h) noting the optical density (OD) of the reaction mixture of standard glucose solutions (step b) and sample (step f) at 585 nm or 635 nm, against air, i) drawing a correlation between the OD values of above sample with OD values of standard glucose solutions, j) multiplying the OD value of sample (step h) with a correction factor of 1.2, comparing this value (A) with the OD value of standard glucose solution of
COD value 320 to 535 mg/l, k) multiplying value (A) with the compared COD value of standard Glucose solution and divided by the respective OD value of the glucose standard (B) and
1) then multiply value (B) with a dilution factor (in case of diluted sample) to obtain the COD value of the sample in terms of mg/l.
In yet another embodiment, in step d, the dilution of samples provide dark brown reaction mixture falling in the range of 10 to 500 for approximate cod values of 10000 mg/l and above as given in Table 1 (e) and further dilution of nil to 31 is done to bring the COD in the range of 300 to 500 mg/l as given in Table 1 (f).
In yet another embodiment, in step (e), the samples provide yellowish to blackish brown coloured reaction mixture falling in the range of 100 to 9500 mg/l COD and the samples are further diluted to 31 times to obtain a diluted sample in the COD range of 300 to 500 mg/l, according to the Tables l (e) and 1 (f).
In yet another embodiment, in step (d) the dilution of samples and color groups range from (A) to (G) for approximate COD values lying in the range of 100 to 9500 mg/l as given in table 1 (d).
In one embodiment of the present invention, the Dilution Factor is the total volume used divided by volume of the sample.
In another embodiment, the effluent used is selected from domestic, industrial, municipal, agricultural and other waste material sources.
In still another embodiment of the invention, the waste material is in the form of solid, liquid, semi-solid or viscous forms.
In yet another embodiment, the reagents used are HgS04, glucose standard solutions, K2Cr207 solution and H2SO4-silver sulfate reagent.
In yet another embodiment, the volume of the test sample or standard solution used ranges from 20 to 100 ml.
In yet another embodiment, the incubation is carried out for a period in the range between 15 seconds to 1 minute.
In yet another embodiment, the estimated COD is in the range between 80 to 106700 mg/L.
In yet another embodiment, the glucose concentration tested is ranging between 50 to 100000 mg/L.
In yet another embodiment, the amount of HgS04 used in the test samples is from 10 mg to 30 mg.
In yet another embodiment, the concentration of K2Cr207 used in the test samples is from 0.25 Normal to 0.30 Normal.
In yet another embodiment, the quantity of H2SO4-silver sulfate reagent used in the test samples is 1. 5 mL.
In yet another embodiment, the COD color chart is applicable for the COD values ranging between 100 to 10,000 mg/L.
In yet another embodiment, the test samples having COD value more than 10000 mg/L is diluted appropriately,
In yet another embodiment, the OD (optical density) of the sample is read at the wavelengths 585 and 635 nm.
In yet another embodiment, the optical density readings are measured for the COD values ranging from 320 to 535 mg/L.
In yet another embodiment, the sample is in the form of slurry.
In yet another embodiment, the sample used for COD estimation comprises of agricultural waste, municipal market waste, fruit and food industry waste, beverages, chemicals, microbes and animal waste etc.
In yet another embodiment of the present invention, the kit for estimation of
Chemical Oxygen Demand (COD) which may comprise of : 1. Reagents such as: A. HgS04 (solid), B. Glucose standard solutions ranging from 300 to 500 mg/L, C. K2Cr207 solution (0.25 to 0.3 N), D.
H2SO4-silver sulfate reagent,
2. a glass vial,
3. a photometric cell,
4. reference tables 1 (e) and 1 (f), 5. a photometer suitable for wave lengths in the range of 585 to 635 nm.
Having now generally described this invention, a further understanding can be obtained by reference to certain specific examples, which provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.
Figure 1 is a colour chart for various values of COD and colour code, together with black and white versions of those colours.
In the specification and claims, where reference is made to figure 1 and the colours therein, the following descriptive term for the colours can also be used. Generally, the colours change gradually from a deep yellow to a grey blue between a COD value of 100mg/L and 2500 mg/L. Between COD values of 3000 and 100,000 mg/L the colour varies from dirty brown to black. Assistance as to the colour can also be gained from the descriptions in the tables 1 a to 1f.
More specifically, the colours represented against COD in mg/L are as follows : 100 deep yellow 150 pale deep yellow 200 dark mid yellow 250 mid yellow 300 pale mid yellow 350 pale yellow-green 400 mid yellow-green 450 yellow-green 500 deep yellow-green 550 pale green 600 mid green 650 deep green-blue 700 pale green-blue 750 pale blue 800 mid pale blue 850 deep pale blue 900 pale mid blue 950 mid blue 1000 deep mid blue 3000 pale dirty brown 3500 dirty brown 4000 deep dirty brown 4500 pale mid brown 5000 mid brown 5500 dark mid brown 6000 pale cola brown 6500 cola brown 7000 dark cola brown 7500 very dark cola brown 8000 pale peat brown 8500 mid peat brown 9000 dark peat brown 9500 very dark peat brown 10000 very pale dark brown 20000 pale dark brown 30000 medium dark brown 40000 deep dark brown 50000 brown-black 1500 pale gray-blue 2000 gray-blue 2500 deep gray blue 100000 black
EXAMPLE 1
Dissolved 0.5 and 5 g glucose in 50 mL distilled water, separately. Aliquots from the stock solutions were taken and diluted with water to achieve different concentrations in the range of 200 to 5000 (COD: 213 to 5335 mg/L) and 10000 to 100000 mg/L (COD: 10670 to 106700 mg/L), respectively. Weighed 0.02 g HgS04 in separate 15 mL and 50 mL test tubes. 1.0 mL of glucose sample was added to each test tube and shake well. 0.5 mi of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 1 min of incubation. The color varied with concentration. In 200 to 5000 mg/L glucose solutions, the color varied from
C200 to C5000. At 5000 mg/L glucose and higher concentrations, the final color was always turbid. However, at concentration above 10000 mg/L glucose concentrations, the final color was always brown (C10000) and turbid. Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with initial COD concentration of 10000 or more, the sample needs to be diluted and its COD, reestimated by taking the dilution factor and color of the reaction mixture into consideration.
Table 1 : Correlation between COD concentration and color of the reaction mixture.
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Glucose COD of Glucose Color of the Concentration the solution reaction (mg/L) (mg/L) mixture ------------------------------------------------------------------------------------------------00 (Blank) 0.0 COO 200 213.4 C200 250 266.7 C250 300 320.1 C300 350 373.4 C350 400 426.8 C400 450 480.1 C450 500 533.5 C500
600 640.2 C600 700 746.9 C700 800 853.6 C800 900 960.3 C900 1000 1067.0 C100 1500 1600.5 C1500 2000 2134.0 C2000 2500 2667.5 C2500 3000 3201.0 C3000 3500 3734.5 C3500 4000 4268.0 C4000 4500 4801.5 C4500 5000 5335.0 C5000 10000 10670.0 C10000 50000 53350.0 C50000 100000 106700. 0 C100000 --------------------------------------------------------------------------------------------------------
EXAMPLE 2
Dissolved 0.5 and 5 g glucose in 50 mL and 100 mL distilled water, respectively.
Aliquots from the stock solutions were taken and diluted with water to achieve different concentrations in the range of 50 to 5000 (COD: 80 to 5335 mg/L) and 5500 to 100000 mg/L (COD: 5868 to 106700 mg/L), respectively. Weighed 0.02 g HgS04 in separate 15 mL and 50 mL test tubes. 1.0 mL of glucose sample was added to each test tube and shake well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 1 min of incubation. The color varied with concentration. In 50 to 9500 mg/L glucose solutions, the color varied from C50 to C9500. At 5500 mg/L glucose and higher concentrations, the final color was always turbid. However, at concentration above 10000 mg/L glucose concentrations, the final color was always C10000. Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with initial COD concentration of 10000 or more, the sample needs to be diluted and its COD, reestimated by taking the dilution factor and color of the reaction mixture into consideration.
Table 2 : Correlation between COD concentration and color of the reaction mixture.
------------------------------------------------------
Glucose COD of Color
Concen Glucose of the tration solution reaction (mg/L) (mg/L) mixture 00 (Blank) 0.0 COO 50 80.3 C50 100 106.7 C100 150 241.0 C150 200 213.4 C200 250 266.7 C250 300 320.1 C300 350 373.4 C350 400 426.8 C400 450 480.1 C450 500 533.5 C500 550 583.8 C550 600 640.2 C600 650 693.5 C650 700 746.9 C700 750 800.2 C750 800 853.6 C800 850 906.9 C850 900 960.3 C900 950 1013.6 C950 1000 1067.0 C1000 1100 1173.7 C1100 1200 1280.4 C1200 1300 1387.1 C1300 1400 1493.8 C1400 1500 1600.5 C1500 1600 1707.2 C1600 1700 1813.9 C1700 1800 1920.6 C1800 1900 2027.3 C1900 2000 2134.0 C2000 2500 2667.5 C2500 3000 3201.0 C3000 3500 3734.5 C3500 4000 4268.0 C4000 4500 4801.5 C4500 5000 5335.0 C5000 5500 5868.5 C5500 6000 6402.0 C6000 6500 6935.5 C6500 7000 7469.0 C7000 7500 8002.5 C7500 8000 8536.0 C8000 8500 9069.5 C8500 9000 9603.0 C9000 9500 10136.5 C9500 10000 10670.0 C10000 15000 16005.0 C15000 20000 21340.0 C20000 30000 32010.0 C30000 40000 42680.0 C40000 50000 53350.0 C50000
100000 106700.0 C100000 -----------------------------------------------------------
EXAMPLE 3
Dissolved 0.5 g glucose in 50ml distilled water. Aliquote from the stock solution were taken and diluted with water to achieve different concentrations in the range of 100 to 2000 mg/L (COD: 106.7 to 2134 mg/L). Weighed 0.02 g HgS04 in separate 15 mL and 25mL test tubes. 1.0 ml of glucose sample was added to each test tube and shake well. 0.5 ml of K2Cr207 was added to each sample. 1.5 ml H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 1 min of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 100 to 2000 mg/L glucose solutions, the color varied from C100 to
C2000. At 100 to 800 mg/L glucose concentrations, OD 585 varied from 0.104 to 0.307 and OD 635 varied from 0.092 to 0.276. In the COD range of 106.7 to 640.2 mg/L the OD 585 and OD 635 there was an incremental difference of 0.030 and 0.027 for each 106.7 mg/L COD increase, respectively. At different wavelengths, OD became stable at 1000 mg/L glucose and higher concentrations. Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with initial OD concentration of 100 to 640 mg/L, OD 585 or OD 635 can be recorded for obtaining more values that are precise.
Table 3: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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Glucose COD of Color OD 585 nm OD 635 nm Concen Glucose of the of the of the tration solution reaction reaction reaction (mg/L) (mg/L) mixture mixture mixture ---------------------------------------------------------------------------------------------100 106.7 C100 0.104 0.092 200 213.4 C200 0.133 0.117 300 320.1 C300 0.164 0.143 400 426.8 C400 0.196 0.165 500 533.5 C500 0.222 0.193 600 640.2 C600 0.252 0.226 800 853.6 C800 0.307 0.276 1000 1067.0 C1000 0.362 0.332 1200 1280.4 C1200 0.347 0.316
1400 1493.8 C1400 0.351 0.323 1600 1707.2 C1600 0.354 0.354 1800 1920.6 C1800 0.344 0.328 2000 2134.0 C2000 0.358 0.343 ------------------------------------------------------------------------------------------
EXAMPLE 4 :
Dissolved 1 g glucose in 100mL disti)) ed water. Aliquots from the stock solution were taken and diluted with water to achieve different concentrations in the range of 100 to 2000 mg/L (COD: 106.7 to 2134 mg/L). Weighed 0.02 g HgS04 in separate 15 mL and 25mL test tubes. 1.0 mL of glucose sample was added to each test tube and shake well. 0.5 ml of K2Cr207 was added to each sample. 1.5 ml H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 30 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 100 to 2000 mg/L glucose solutions, the color varied from C100 to
C2000. At 100 to 1000 mg/L glucose concentrations, OD 585 varied from 0.109 to 0.347 and OD 635 varied from 0.096 to 0. 317. In the COD range of 106.7 to 640.2 mg/L the OD 585 and OD 635 there was an incremental difference of 0.027 and 0.026 for each 106.7 mg/L COD increase, respectively. At different wavelengths, OD became stable at 1000 mg/L glucose and higher concentrations. Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with initial COD concentration of 100 to 640 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 4: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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Glucose COD of Color OD 585 nm OD 635 nm Concen Glucose of the of the of the tration solution reaction reaction reaction (mg/L) (mg/L) mixture mixture mixture -----------------------------------------------------------------------------------------------100 106.7 C100 0.109 0.096 200 213.4 C200 0.132 0.116 300 320.1 C300 0.161 0.142 400 426.8 C400 0.193 0.164 500 533.5 C500 0.222 0.195
600 640.2 C600 0.246 0.226 800 853.6 C800 0.300 0.274 1000 1067.0 C1000 0.347 0.317 1200 12804 C1200 0.350 0.321 1400 1493.8 C1400 0.341 0. 326 1600 1707.2 C1600 0.352 0.332 1800 1920.6 C1800 0.354 0.331 2000 2134.0 C2000 0. 354 0.349 ----------------------------------------------------------------------------------------------------
EXAMPLE 5 :
Dissolved 0.25 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different concentrations in the range of 100 to 500 mg/L (COD: 106.7 to 533.5 mg/L). Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose sample was added to each test tube and shake well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 30 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 100 to 500 mg/L glucose solutions, the color varied from C100 to
C500. At 100 to 500 mg/L glucose concentrations, OD 585 varied from 0.106 to 0.223 and OD 635 varied from 0.089 to 0.199. In the COD range of 106.7 to 533.5 mg/L the OD 585 and OD 635 there was an incremental difference of 0.029 and 0.027 for each 106.7 mg/L COD increase, respectively. Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with initial COD concentration of 106.7 to 533.5 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 5: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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Glucose COD of Color OD 585 nm OD 635 nm Concen Glucose of the of the of the tration solution reaction reaction reaction (mg/L) (mg/L) mixture mixture mixture
--------------------------------------------------------------------------------------------------100 106.7 C100 0.106 0.089 200 213.4 C200 0.133 0.116 300 320.1 C300 0.162 0.144 400 426.8 C400 0.192 0.166 500 533.5 C500 0.223 0.199 --------------------------------------------------------------------------------------------
EXAMPLE 6 :
Dissolved 0.2 g glucose in 50 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different concentrations in the range of 100 to 500 mg/L (COD: 106.7 to 533.5 mg/L). Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 ml of glucose sample was added to each test tube and shake well. 0.5 ml of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 100 to 500 mg/L glucose solutions, the color varied from C100 to
C500. At 100 to 500 mg/L glucose concentrations, OD 585 varied from 0.104 to 0.225 and OD 635 varied from 0.089 to 0.196. In the COD range of 106.7 to 533.5 mg/L the OD 585 and OD 635 there was an incremental difference of 0.030 and 0.028 for each 106.7 mg/L COD increase, respectively. Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with initial COD concentration of 106.7 to 533.5 mg/L, OD 585 or OD 635 can be recorded for obtaining more accurate values.
Table 6: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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Glucose COD of Color OD 585 nm OD 635 nm Concen Glucose of the of the of the tration solution reaction reaction reaction (mg/L) (mg/L) mixture mixture mixture --------------------------------------------------------------------------------------------100 106.7 C100 0.104 0.089 200 213.4 C200 0.132 0.115 300 320.1 C300 0.164 0.145 400 426.8 C400 0.196 0.165 500 533.5 C500 0.225 0.196
EXAMPLE 7 : Dissolved 0. 3 g glucose in 50ml distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different concentrations in the range of 300 to 500 mg/L (COD: 320.1 to 533.5 mg/L). Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mi of glucose sample was added to each test tube and shake well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 against air. The color varied with concentration. In 300 to 500 mg/L glucose solutions, the color varied from C300 to C500. At 300 to 500 mg/L glucose concentrations, OD 585 varied on an average from 0.158 to 0.210. In the COD range of 320.1 to 533.5 mg/L the OD 585 there was an incremental difference of 0.026 for each 106.7 mg/L COD increase. Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with initial COD concentration of 320.1 to 533.5 mg/L, OD 585 can be recorded for obtaining values that are more precise.
Table 7: Correlation between COD concentration, color of the reaction mixture and their OD at 585 nm.
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S. Glucose COD of Color OD 585 nm No. Concen Glucose of the of the tration solution reaction reaction (mg/L) (mg/L) mixture mixture ---------------------------------------------------------------------------------------------------1.300 320.1 C300 0.154 2.300 320.1 C300 0.168 3.300 320.1 C300 0.162 4.300 320.1 C300 0.155 5.300 320.1 C300 0.153 6 300 320.1 C300 0.158 7 300 320.1 C300 0.157 1.400 426.8 C400 0.178
2.400 426.8 C400 0.207 3.400 426.8 C400 0.189 4.400 426.8 C400 0.183 5.400 426.8 C400 0.181 6.400 426.8 C400 0.185 7.400 426.8 C400 0.186 1.500 533.5 C500 0.193 2.500 533.5 C500 0.234 3.500 533.5 C500 0.207 4.500 533.5 C500 0.215 5.500 533.5 C500 0.207 6.500 533.5 C500 0.208 7. 500 533. 5 C500 0. 210 -----------------------------------------------------------------------------------------------------
EXAMPLE 8 :
Dissolved 0.5 g glucose in 100 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 533 mg/L. A 20 mL sample of anaerobically digested damaged
wheat grain slurry initially inoculated with Aspero/us n/oer for 10 days was taken. gillus RLqff for 10 days was taken.
COD of the sample was estimated to be 52300 mg/L. (By Merck method and read on photometer. ) Based on the estimated COD value, diluted samples were prepared in water to achieve a final COD in the range of 415 to 520 mg/L. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 320 to 533 mg/L glucose solutions, the color varied from C300 to C550. At 320 to 533 mg/L glucose concentrations, average OD 585 varied from 0.152 to 0.192 and OD 635 varied from 0.141 to 0. 183. In the COD range of 320.1 to 533.5 mg/L the OD 585 and OD 635 there was an incremental difference of 0.026 and 0.024 for each 106.7 mg/L COD increase, respectively. On the other hand, color of the final sample reaction mixture varied from C400 to C500.
At 415.5 to 519.3 mg/L COD concentrations of the sample, average OD 585 varied from 0.145 to 0.169 and OD 635 varied from 0.129 to 0. 148. In this COD range, there was an incremental difference of 0.024 and 0.020 for each 103.8 mg/L COD increase at OD 585 and OD 635, respectively.
Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 415.5 to 519.3 mg/L, OD 585 or OD 635 can be recorded for obtaining values that is more precise.
Table 8: Correlation between COD. concentration, color of the reaction mixture and their OD at different wave lengths.
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COD (mg/L) Color of the OD of the reaction mixture reaction mixture 585 nm 635 nm Glucose : Glucose: 320 C300 0.154 0.142 C300 0.150 0.139 C300 0.153 0.142 426 C400 0.178 0.166 C400 0.175 0.162 C400 0.181 0.169 533 C550 0.192 0.183 C550 0.190 0.180 C550 0.194 0.185 Sample : Damaged wheat grain slurry 415.5 C400 0.142 0.128 C400 0.152 0.132 C400 0.141 0.128 467.9 C450 0.146 0.128 C450 0.149 0.135 C450 0.147 0.128 519.3 C500 0.180 0.161
C500 0.166 0.140 C500 0. 162 0. 142 EXAMPLE 9:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 533 mg/L. A 30 mL sample of anaerobically digested damaged wheat grain slurry initially inoculated with Bac llus licheniformis was taken. COD of the sample was estimated to be 54700 mg/L. (By Merck method and read on photometer. ) Based on the estimated COD value, diluted samples were prepared in water to achieve a final COD in the range of 300 to 500 mg/L. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 320 to 533 mg/L glucose solutions, the color varied from C300 to C550. At 320 to 533 mg/L glucose concentrations, average OD 585 varied from 0.168 to 0.234 and OD 635 varied from 0.151 to 0.213. In the COD range of 320.1 to 533.5 mg/L the OD 585 and OD 635 there was an incremental difference of 0.033 for each 106.7 mg/L COD increase. On the other hand, color of the final sample reaction mixture varied from C300 to C550.
At 300 to 500 mg/L COD concentrations of the sample, average OD 585 varied from 0.136 to 0.175 and OD 635 varied from 0.123 to 0.156. In this COD range, there was an incremental difference of 0.020 and 0.017 for each 100 mg/L COD increase at
OD 585 and OD 635, respectively.
Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining values that is more precise.
Table 9: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD (mg/L) Color of the OD of the reaction mixture reaction mixture 585 nm 635 nm Glucose : 320 C300 0.164 0.146 C300 0.167 0.152 C300 0.172 0.154 426 C400 0.198 0.182 C400 0.214 0.194 C400 0.209 0.193 533 C550 0.235 0.212 C550 0.236 0.217 C550 0.231 0.211 Sample : Damaged wheat grain slurry 300.7 C300 0.140 0.129 C300 0.135 0. 121 C300 0.134 0.121 411.6 C400 0.158 0.146 C400 0.156 0.140 C400 0.157 0.141 500.6 C500 0.174 0.155 C500 0.175 0.160 C500 0. 175 0. 155 EXAMPLE 10:
Dissolved 0. 2-g glucose in 50 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 533 mg/L. A 25-mL sample of anaerobically digested damaged wheat grain slurry was taken. COD of the sample was estimated to be 61300 mg/L.
(By Merck method and read on photometer. ) Based on the estimated COD value, diluted samples were prepared in water to achieve a final COD in the range of 335 to 505 mg/L. Weighed 0.02 g HgS04 in separate 15-mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 320 to 533 mg/L glucose solutions, the color varied from C300 to C550. At 320 to 533 mg/L glucose concentrations, average OD 585 varied from 0.162 to 0.207 and OD 635 varied from 0.145 to 0.186. In the COD range of 320.1 to 533.5 mg/L, the OD 585 and OD 635 there was an incremental difference of 0.023 and 0.025 for each 106.7 mg/L COD increase, respectively. On the other hand, color of the final sample reaction mixture varied from C350 to C500.
At 335 to 505 mg/L COD concentrations of the sample, average OD 585 varied from 0.132 to 0.169 and OD 635 varied from 0.116 to 0. 151. In this COD range, there was an incremental difference of 0.019 and 0.022 for each 85 mg/L COD increase at OD 585 and OD 635, respectively.
Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 335 to 505 mg/L, OD 585 or OD 635 can be recorded for obtaining values that is more precise.
Table 10: Correlation between COD concentration, color of the reaction mixture and their OD at different wavelengths.
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COD (mg/L) Color of the OD of the reaction mixture reaction mixture 585 nm 635 nm Glucose : 320 C300 0.160 0.143 C300 0.164 0.147 C300 0.162 0.145 426 C400 0.190 0.184 C400 0.191 0.176 C400 0.187 0.168
533 C550 0.207 0.190 C550 0.206 0.184 C550 0.207 0.185 Sample : Damaged wheat grain slurry 337.1 C350 0.128 0.112 C350 0.134 0.119 C350 0. 1 35 0.117 421.3 C400 0.153 0.135 C400 0.151 0.134 C400 0.155 0.137 504.6 C500 0.168 0.149 C500 0.169 0.149 C500 0. 169 0. 154 --------------------------------------------------------------------------------------------------
EXAMPLE 11 : Dissolved 0.1 g glucose in 50 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 533 mg/L. A 40-mL sample of anaerobically digested damaged wheat grain slurry initially treated with Aspergillus niGer for 10 days and inoculated with Bacillus subtilis was taken. COD of the sample was estimated to be 6600 mg/L.
(By Merck method and read on photometer. ) Based on the estimated COD value, diluted samples were prepared in water to achieve a final COD in the range of 330 to 530 mg/L. Weighed 0.02 g HgS04 in separate 15-mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulfate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 320 to 533 mg/L glucose solutions, the color varied from C300 to C550. At 320 to 533 mg/L glucose concentrations, average OD 585 varied from 0.155 to 0.215 and OD 635 varied from 0.144 to 0. 194. In the COD range of 320.1 to 533.5 mg/L, the OD 585 and OD 635 there was an incremental difference of 0.030 and 0.025 for each 106.7-mg/L COD increase, respectively. On the other hand, color of the final sample reaction mixture varied from C350 to C550.
At 330 to 530 mg/L COD concentrations of the sample, average OD 585 varied from 0.137 to 0.174 and OD 635 varied from 0.121 to 0. 153. In this COD range, there was an incremental difference of 0.019 and 0.016 for each 100-mg/L COD increase at
OD 585 and OD 635, respectively.
Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 330 to 530 mg/L, OD 585 or OD 635 can be recorded for obtaining values that is more precise.
Table 11: Correlation between COD concentration, color of the reaction mixture and
their OD at different wavelengths.
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COD (mg/L) Color of the OD of the reaction mixture reaction mixture 585 nm 635 nm Glucose : 320 C300 0.154 0.143 C300 0.155 0.142 C300 0.157 0.146 426 C400 0.182 0.170 C400 0.182 0.168 C400 0.184 0.170 533 C550 0.206 0.187 C550 0.208 0.190 C550 0.230 0.205 Sample : Damaged wheat grain slurry 331 C350 0.134 0.118 C350 0.138 0.126 C350 0.138 0.120 429 C400 0.157 0.139 C400 0.153 0.135 C400 0.154 0.134 529 C500 0.172 0.152
C500 0.171 0.151 C500 0. 178 0. 156 EXAMPLE 12:
Dissolved 0.2 g glucose in 50 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 533 mg/L. A 30 mL sample of partially digested vegetable waste slurry was taken. COD of the sample was estimated to be 9640 mg/L (By Merck method and read on photometer). Based on the estimated COD value, diluted samples were prepared in water to achieve a final COD in the range of 290 to 480 mg/L. Weighed 0.02 g HgS04 in separate 15-mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulfate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 320 to 533 mg/L glucose solutions, the color varied from C300 to C550. At 320 to 533 mg/L glucose concentrations, average OD 585 varied from 0.153 to 0.207 and OD 635 varied from 0.142 to 0.188. In the COD range of 320.1 to 533.5 mg/L the OD 585 and OD 635 there was an incremental difference of 0.027 and 0.023 for each 106.7 mg/L COD increase, respectively. On the other hand, color of the final sample reaction mixture varied from C300 to C500.
At 290 to 480 mg/L COD concentrations of the sample, average OD 585 varied from 0.138 to 0.157 and OD 635 varied from 0.123 to 0.141. In this COD range, there was an incremental difference of 0.009 for each 95 mg/L COD increase at OD 585 and
OD 635.
Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 290 to 480 mg/L, OD 585 or OD 635 can be recorded for obtaining values that is more accurate.
Table 12: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
COD (mg/L) Color of the OD of the reaction mixture reaction mixture 585 nm 635 nm Glucose : 320 C300 0.152 0.142 C300 0.156 0.145 C300 0.151 0.139 426 C400 0.181 0.169 C400 0.183 0.170 C400 0.180 0.168 533 C550 0. 205 0.186 C550 0.212 0.194 C550 0.204 0.184 Sample : Vegetable waste slurry 290 C300 0.140 0.123 C300 0.132 0.120 C300 0.141 0.127 386 C400 0.158 0.143 C400 0.151 0.140 C400 0.144 0.128 482 C500 0.162 0.146 C500 0.156 0.141 C500 0. 153 0. 137 --------------------------------------------------------------------------------------------
EXAMPLE 13 :
Dissolved 0.25 g glucose in 50 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 533 mg/L. A 50 mL sample of partially digested vegetable waste slurry was mixed with anaerobically digested damaged wheat grain slurry. COD of the sample was estimated to be 9400 mg/L (By Merck method and read on photometer). Based on the estimated COD value, diluted samples were prepared in water to achieve a final COD in the range of 297 to 533 mg/L. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 320 to 533 mg/L glucose solutions, the color varied from C300 to C500. At 320 to 533 mg/L glucose concentrations, average OD 585 varied from 0.158 to 0.208 and OD 635 varied from 0.138 to 0.187. In the COD range of 320.1 to 533.5 mg/L the OD 585 and OD 635 there was an incremental difference of 0.025 and 0.025 for each 106.7 mg/L
COD increase, respectively. On the other hand, color of the final sample reaction mixture varied from C300 to C500.
At 297 to 533 mg/L COD concentrations of the sample, average OD 585 varied from 0.132 to 0.179 and OD 635 varied from 0.118 to 0. 162. In this COD range, there was an incremental difference of 0.023 and 0.027 for each 118 mg/L COD increase at OD 585 and OD 635, respectively.
Hence, for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 297 to 533 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 13: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD (mg/L) Color of the OD of the reaction mixture reaction mixture 585 nm 635 nm Glucose : 320 C300 0.167 0.148 C300 0.154 0.135 C300 0.152 0.131 426 C400 0.188 0.167 C400 0.185 0.162 C400 0.181 0.159 533 C550 0.215 0.195 C550 0.206 0.184 C550 0.202 0.181 Sample : Vegetable waste slurry + Damaged wheat grain slurry
297 C300 0.126 0.111 C300 0.138 0.124 C300 0.133 0.118 445 C450 0.168 0.152 C450 0.164 0.148 C450 0.168 0.152 533 C550 0.188 0.169 C550 0.180 0.163 C550 0. 169 0.153 -----------------------------------------------------------------------------------------------------
EXAMPLE 14 :
Dissolved 0.15 g glucose in 50 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations In the range of 320 to 533 mg/L. A 30 mL sample of apple pomace soaked for 1 day was taken. COD of the sample was estimated to be 51700 mg/L (By Merck method and read on photometer). Based on the estimated COD value, diluted samples were prepared in water to achieve a final COD in the range of 310 to 517 mg/L. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 ml of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 320 to 533 mg/L glucose solutions, the color varied from C300 to C550. At 320 to 533 mg/L glucose concentrations, average OD 585 varied from 0.157 to 0.210 and OD 635 varied from 0.142 to 0.189. In the COD range of 320.1 to 533.5 mg/L the OD 585 and OD 635 there was an incremental difference of 0.026 and 0.024 for each 106.7 mg/L COD increase, respectively. On the other hand, color of the final sample reaction mixture varied from C300 to C500.
At 310 to 517 mg/L COD concentrations of the sample, average OD 585 varied from 0.141 to 0.186 and OD 635 varied from 0.126 to 0. 167. In this COD range, there was an incremental difference of 0.022 and 0.020 for each 104 mg/L COD increase at
OD 585 and OD 635, respectively. Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 310 to 517 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 14: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD (mg/L) Color of the OD of the reaction mixture reaction mixture 585 nm 635 nm Glucose : 320 C300 0.157 0.142 C300 0.154 0.139 C300 0.159 0.146 426 C400 0.186 0.168 C400 0.185 0.162 C400 0.187 0.170 533 C550 0.216 0.196 C550 0.209 0.188 C550 0.207 0.183 Sample : Apple pomace 310 C300 0.140 0.126 C300 0.142 0.126 C300 0.140 0.126 413 C400 0.171 0.152 C400 0.165 0.148 C400 0.165 0.147 517 C500 0.186 0.166 C500 0.187 0.168 C500 0. 186 0. 167 EXAMPLE 15:
Dissolved 0.1 g glucose in 50 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different concentrations in the range of 320 to 533 mg/L A 50 mL sample was prepared by mixing apple pomace soaked for 1 day with digested damaged wheat grains and partially digested vegetable market waste. COD of the sample was estimated to be 40300 mg/L (By Merck method and read on photometer). Based on the estimated COD value, diluted samples were prepared in water to achieve a final COD in the range of 310 to 497 mg/L. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mi of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. The color varied with concentration. In 320 to 533 mg/L glucose solutions, the color varied from C300 to C550. At 320 to 533 mg/L glucose concentrations, average OD 585 varied from 0.159 to 0.212 and OD 635 varied from 0.142 to 0.190. In the COD range of 320. 1 to 533.5 mg/L the OD 585 and OD 635 there was an incremental difference of 0.026 and 0.024 for each 106.7 mg/L COD increase, respectively. On the other hand, color of the final sample reaction mixture varied from C300 to C500.
At 310 to 497 mg/L COD concentrations of the sample, average OD 585 varied from 0.125 to 0.169 and OD 635 varied from 0.112 to 0. 155. In this COD range, there was an incremental difference of 0. 022 and 0.021 for each 93 mg/L COD increase at OD 585 and OD 635, respectively.
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 310 to 497 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 15: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD (mg/L) Color of the OD of the reaction mixture reaction mixture 585 nm 635 nm Glucose : 320 C300 0.160 0.144 C300 0.157 0.141 C300 0.159 0.142 426 C400 0.187 0.170 C400 0. 185 0.167 C400 0.189 0.172 535 C550 0.220 0.199 C550 0.209 0.187 C550 0.207 0.184
Sample : Apple pomace+ Vegetable waste slurry + Damaged wheat grain slurry 310 C300 0.126 0.114 C300 0.126 0.112 C300 0.124 0.111 404 C400 0.148 0.136 C400 0.154 0.146 C400 0.152 0.141 497 C500 0.171 0.159 C500 0.168 0.154 C500 0. 167 0. 152 ---------------------------------------------------------------------------------------------------
EXAMPLE 16:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of partially digested vegetable waste slurry mixed with potassium hydrogen phosphate salt was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0. 157 to 0. 207 and 0. 142 to 0. 189, respectively).
COD of the sample was estimated to be 777 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 750 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 824 and 852 mg/L, respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.94 = COD value (Merck Method) or our COD value (at OD 635) x 0.91 = COD value (Merck
Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 16: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 12 3456 Values at OD 585 nm Glucose : 320 NA C300 0.162 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.206 NA NA Sample : Vegetable waste (filtrate) + Potassium hydrogen phosphate Nil C1500 0.240 =1500# =1500 5 C150 0.101 150# 750 2 C400 0.150 412 824 Values at OD 635 nm Glucose 320 NA C300 0.150 NA NA 426 NA C400 0.167 NA NA 535 NA C550 0.187 NA NA Sample : Vegetable waste (filtrate) + Potassium hydrogen phosphate Nil C1500 0. 40 =1500# =1500 5 C150 0.101 150# 750 2 C400 0. 150 426 852 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 17 :
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of partially digested palm oil mill effluent (filtrate) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and
OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.159 to 0.205 and 0.149 to 0.183, respectively).
COD of the sample was estimated to be 687 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 500 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 874 and 882 mg/L, respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.79 = COD value (Merck Method) or our COD value (at OD 635) x 0.79 = COD value (Merck
Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 17: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.205 NA NA Sample : Palm oil mill effluent (filtrate) Nil C500 0.236 #500# #500 2 C450 0.159 437 874 Values at OD 635 nm Glucose : 320 NA C300 0.149 NA NA 426 NA C400 0.166 NA NA 535 NA C550 0.183 NA NA Sample : Palm oil mill effluent (filtrate) Nil C500 0.213 #500# #500 2 C450 0. 143 441 882 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 18:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of partially digested vegetable waste slurry mixed was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 1930 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 1400 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 1280 and 1288 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.51 =
COD value (Merck Method) or our COD value (at OD 635) x 1.50 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 18: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 12 3456 Values at OD 585 nm Glucose : 320 NA C300 0.161 NA NA 426 NA C400 0.187 NA NA 535 NA C550 0.202 NA NA Sample : Vegetable waste slurry Nil C1400 0.294 1400# 1400 4 C320 0.134 320 1280 Values at OD 635 nm Glucose : 320 NA C300 0.144 NA NA 426 NA C400 0.167 NA NA 535 NA C550 0.184 NA NA Sample : Vegetable waste slurry Nil C1400 0.268 #1400# # 1400 4 C320 0. 121 322 1288 # : COD as deducible from Table 2 given in Example 2. D: Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 4 to 15 given in Examples 4 to 15.
EXAMPLE 19:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of partially digested Vegetable waste slurry (filtrate) mixed was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 1033 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 1500 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 1632 and 1652 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.63 =
COD value (Merck Method) or our COD value (at OD 635) x 0.62 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 19: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose: 320 NA C300 0.159 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.205 NA NA Sample : Vegetable waste slurry (filtrate) Nil C1500 0.257 =1500# =1500 4 C400 0.148 408 1632 Values at OD 635 nm Glucose : 320 NA C300 0.145 NA NA 426 NA C400 0.166 NA NA 535 NA C550 0.187 NA NA Sample : Vegetable waste slurry (filtrate) Nil C1500 0. 236-1500# =1500 4 C400 0. 134 413 1652 ---------------------------------------------------- #: COD as deducible from Table 2 given in Example 2. D: Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 20:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (filtrate) mixed with vegetable waste slurry (filtrate) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 4067 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 3000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 4170 and 4180 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.97 =
COD value (Merck Method) or our COD value (at OD 635) x 0.97 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 20: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose: 320 NA C300 0.161 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.206 NA NA Sample: Damaged wheat grain (filtrate) + Vegetable waste slurry (filtrate) Nil C1400 1.031 #1400# #1400 5 C600 0.234 #600# #3000 10 C400 0.152 417 4170 Values at OD 635 nm Glucose : 320 NA C300 0.146 NA NA 426 NA C400 0.167 NA NA 535 NA C550 0.186 NA NA Sample : Damaged wheat grain (filtrate) + Vegetable waste slurry (filtrate) Nil C1400 0. 784-1400# =1400 5 C600 0.213 =600# =3000 10 C400 0. 137 418 4180 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 21:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (filtrate) mixed with vegetable waste slurry was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 ml of K2Cr207 was added to each sample. 1.5 mL
H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/l corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 4059 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 2900 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 4440 and 4490 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.91 =
COD value (Merck Method) or our COD value (at OD 635) x 0.90 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 21 : Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.186 NA NA 535 NA C300 0. 205 NA NA Sample : Damaged wheat grain (filtrate) + Vegetable waste Nil C2000 0.438 =2000# =2000 5 C600 0.229 #580# #2900 10 C450 0.162 444 4440 Values at OD 635 nm Glucose : 320 NA C300 0.145 NA NA 426 NA C400 0.166 NA NA 535 NA C550 0.187 NA NA Sample : Damaged wheat grain (filtrate) + Vegetable waste Nil C2000 0.378 =2000# =2000 5 C600 0.206 #580# #2900 10 C450 0. 146 449 4490 ------------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 22:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (filtrate) mixed with palm oil mill effluent (filtrate) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
CD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
*COD of the sample was estimated to be 5391 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 3700 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 5344 mg/L.
A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585 or OD 635) x 1.01 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 22: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.161 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.206 NA NA Sample : Damaged wheat grain (filtrate) + Palm oil mill effluent (filtrate) Nil C2000 0.533 #2000# #2000 5 C600 0. 258 =580#-2900 10 C400 0.183 #373# #3730 16.7 C300 0.133 320 5344 Values at OD 635 nm Glucose : 320 NA C300 0.146 NA NA 426 NA C400 0.167 NA NA 535 NA C550 0.186 NA NA Sample : Damaged wheat grain (filtrate) + Palm oil mill effluent (filtrate) Nil C2000 0.442 =2000# -2000 5 C600 0.234 #580# #2900 10 C400 0.165 #373# #3730 16. 7 C300 0. 120 320 5344 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0. 160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 23:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (filtrate) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 ml of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 6250 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 5800 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 8020 and 6700 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.78 =
COD value (Merck Method) or our COD value (at OD 635) x 0.93 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 23: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the 00 Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 12 3456 Va ! ues at OD 585 nm Glucose : Values at OD 585 nm Glucose: 320 NA C300 0.159 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.205 NA NA Sample : Damaged wheat grain (filtrate) Nil C1900 1.325 #1900# #1900 10 C600 0.204 #580# #5800 20 C400 0.146 401 8020 Values at OD 635 nm Glucose : 320 NA C300 0.149 NA NA 426 NA C400 0.166 NA NA 535 NA C550 0.183 NA NA Sample : Damaged wheat grain (filtrate) Nil C1900 1.146 #1900# #1900 10 C600 0.184 #580# #5800 20 C350 0. 130 335 6700 ------------------------------------------------------ # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 24:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (filtrate) slurry was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0. 5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0. 207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 9794 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 10,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 6840 and 6700 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.43 =
COD value (Merck Method) or our COD value (at OD 635) x 1.46 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 24: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.205 NA NA Sample : Damaged wheat grain (filtrate) Nil C10000 0.834 =10000# =10000 20 C350 0.142 342 6840 Values at OD 635 nm Glucose : 320 NA C300 0.145 NA NA 426 NA C400 0.166 NA NA 535 NA C550 0.187 NA NA Sample : Damaged wheat grain (filtrate) Nil C10000 0. 654 =10000# =10000 20 C350 0. 127 335 6700 ----------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T : Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 25:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (filtrate) slurry was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 15502 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 10,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 8000 and 7725 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.94 =
COD value (Merck Method) or our COD value (at OD 635) x 2.01 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 25: Correlation between COD concentration, color of the reaction mixture and their CD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.164 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.205 NA NA Sample : Damaged wheat grain (filtrate) Nil C10000 0.964 > 10000# > 10000 10 C600 0.267 > 600# > 6000 25 C300 0.137 320 8000 Values at OD 635 nm Glucose : 320 NA C300 0.152 NA NA 426 NA C400 0.166 NA NA 535 NA C550 0.184 NA NA Sample : Damaged wheat grain (filtrate) Nil C10000 0.714 > 10000# > 10000 10 C600 0.252 > 600# > 6000 25 C300 0. 122 309 7725 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 26:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Cattle dung slurry was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/l. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 18515 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 10,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 8660 mg/L.
A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585 or OD 635) x 2.14 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 26: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.162 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.205 NA NA Sample : Cattle dung slurry Nil C10000 1.878 =10000# =10000 20 C450 0.157 433 8660 Values at OD 635 nm Glucose : 320 NA C300 0.148 NA NA 426 NA C400 0.171 NA NA 535 NA C550 0.189 NA NA Sample : Cattle dung slurry Nil C10000 1.637 # 10000# # 10000 20 C450 0. 145 433 8660 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 27:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Palm Oil Mill Effluent (Digested) with
Damaged wheat grains (filtrate) slurry was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air.
An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mgll. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0. 175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 19941 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 12,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 10656 and 11355 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.87 =
COD value (Merck Method) or our COD value (at OD 635) x 1.76 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 27: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose.
320 NA C300 0.158 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.205 NA NA Sample : Palm Oil Mill Effluent (Digested) + Damaged wheat grains (filtrate) Nil C10000 6.000* > 10000# > 10000 20 C600 0. 195 600#-12000 33.3 C300 0. 131 320 10656 Values at OD 635 nm Glucose : 320 NA C300 0.137 NA NA 426 NA C400 0.163 NA NA 535 NA C550 0.185 NA NA Sample : Palm Oil Mill Effluent (Digested) + Damaged wheat grains (filtrate) Nil C10000 6.000* > 10000# > 10000 20 C600 0.182 # 600# # 12000 33. 3 C300 0. 122 341 11355 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0. 160, to obtain a COD value in the range of 320 to 535 mg/L (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 28:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Palm Oil Mill Effluent (Digested) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/l. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0. 120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/i corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 22287 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 20,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 15840 and 13560 mg/l, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1. 41 = COD value (Merck Method) or our COD value (at OD 635) x 1. 64 = COD value (Merck Method),
Hence for a preliminary estimate of COD value, color of standard reaction mixture can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 28: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 56 Values at OD 585 nm Glucose : 320 NA C300 0.162 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.205 NA NA Sample: Palm Oil Mill Effluent (Digested) Nil C10000 6.000* > 10000# > 10000 10 C2000 0.345 > 2000# > 20000 50 C250 0.119 250 12500 40 C400 0. 143 396 15840 Values at OD 635 nm Glucose : 320 NA C300 0.148 NA NA 426 NA C400 0.171 NA NA 535 NA C550 0.189 NA NA Sample : Palm Oil Mill Effluent (Digested) Nil C10000 6.000* > 10000# > 10000 10 C2000 0.330 > 2000# > 20000 50 C250 0.109 250 12500 40 C400 0. 131 339 13560 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 29:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Palm Oil Mill Effluent (Digested) with
Apple pomace was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 44620 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 40,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 38640 and 40080 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.15 =
COD value (Merck Method) or our COD value (at OD 635) x 1.11 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 29: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.155 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.205 NA NA Sample : Palm Oil Mill Effluent (Digested) + Apple pomace Nil C10000 6.000* > 10000# > 10000 20 C2000 0.352 > 2000# > 40000 100 C2000 0.220 # 250# # 25000 120 C300 0.132 320 38640 Values at OD 635 nm Glucose : 320 NA C300 0.137 NA NA 426 NA C400 0.163 NA NA 535 NA C550 0.185 NA NA Sample : Palm Oil Mill Effluent (Digested) + Apple pomace Nil C10000 6.000* > 10000# > 10000 20 C2000 0.322 > 2000# > 40000 100 C2000 0. 190 == 250# == 25000 120 C300 0. 119 334 40080 # : COD as deducible from Table 2 given in Example 2. D : Dark. T. Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 30:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Vegetable waste slurry with Apple pomace was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/l. OD 585 and
OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 35484 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 40,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 40000 and 34000 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0. 89 = COD value (Merck Method) or our COD value (at OD 635) x 1.04 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 30: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.163 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.202 NA NA Sample : Vegetable waste slurry+ Apple pomace Nil C10000 6.00* > 10000# > 10000 20 C2000 0.349 > 2000#-40000 100 C400 0.145 400 40000 Values at OD 635 nm Glucose : 320 NA C300 0.147 NA NA 426 NA C400 0.170 NA NA 535 NA C550 0.187 NA NA Sample : Vegetable waste slurry+ Apple pomace Nit C10000 6.00* > 10000# > 10000 20 C2000 0.318 > 2000# 40000 100 C400 0. 130 340 34000 ----------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 31:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (filtrate) with
Apple pomace was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 36018 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 30,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 42600 mg/l. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585 or OD 635) x 0.84 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 31: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.164 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.205 NA NA Sample : Damaged wheat grain (filtrate) + Apple pomace Ni ! C10000 6. 000* > 10000# > 10000 10 C1500 0.442 > 1500# > 15000 50 C600 0.236 > 600# > 30000 100 C400 0.155 426 42600 Values at OD 635 nm Glucose : 320 NA C300 0.152 NA NA 426 NA C400 0.166 NA NA 535 NA C550 0.184 NA NA Sample : Damaged wheat grain (filtrate) + Apple pomace Nil C10000 6.000* > 10000# > 10000 10 C1500 0.377 > 1500# > 15000 50 C600 0.212 > 600# > 30000 100 C400 0. 138 426 42600 ---------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 32:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain slurry with Tea with Sodium sulphate was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 53867 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 100,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 49896 and 51744 mg/L, respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.08 = COD value (Merck Method) or our COD value (at OD 635) x 1.04 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 32: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the 00 Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.163 NA NA 426 NA C400 0.183 NA NA 535 NA C550 0.205 NA NA Sample : Damaged wheat grain + Tea + Sodium sulphate Nil C10000 6.00* > 10000# > 10000 10 C10000 0. 801 * 10000# =100000 154 C300 0.138 324 49896 Values at OD 635 nm Glucose : 320 NA C300 0.150 NA NA 426 NA C400 0.167 NA NA 535 NA C550 0.187 NA NA Sample: Damaged wheat grain + Tea + Sodium sulphate Nil C10000 6.00* > 10000# > 10000 10 C10000 0.801 * #10000# #100000 154 C300 0. 124 336 51744 ----------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D: Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 33:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Apple pomace was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 55890 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 50,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 65875 and 66500 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0. 85 = COD value (Merck Method) or our COD value (at OD 635) x 0.84 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 33: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.161 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.206 NA NA Sample : Apple pomace Ni ! C10000 6. 00* > 10000# > 10000 10 C5000 0.525 =5000# =50000 125 C500 0.171 527 65875 Values at OD 635 nm Glucose : 320 NA C300 0.150 NA NA 426 NA C400 0.167 NA NA 535 NA C550 0.188 NA NA Sample : Apple pomace Nil C10000 6.00* > 10000# > 10000 10 C5000 0. 428 =5000# =50000 125 C500 0. 157 532 66500 ----------------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 34:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain with Tea was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/l. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 58760 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 64800 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 78848 and 84546 mg/L, respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.74 =
COD value (Merck Method) or our COD value (at OD 635) x 0.70 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 34: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.162 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.206 NA NA Sample : Damaged wheat grain + Tea Nil C10000 6.00* > 10000# > 10000 10 C10000 6.00* > 10000# #100000 100 C1500 0.272 #1500# #150000 270 C250 0.124 # 240# # 64800 154 C500 0.164 512 78848 Values at OD 635 nm Glucose : 320 NA C300 0.150 NA NA 426 NA C400 0.167 NA NA 535 NA C500 0.187 NA NA Sample : Damaged wheat grain + Tea Nil C10000 6.00* > 10000# > 10000 10 C10000 6.00* > 10000# =100000 100 C1500 0.272 =1500# -150000 270 C250 0.124 # 240# # 64800 154 C500 0. 160 549 84546 --------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 35:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Trizyme with Tea was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 61088 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 100,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 79156 and 67914 mg/L, respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.77 = COD value (Merck Method) or our COD value (at OD 635) x 0.90 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 35: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.163 NA NA 426 NA C400 0.183 NA NA 535 NA C550 0.205 NA NA Sample : Trizyme + Tea Nil C10000 6. 00* > 10000# > 10000 50 C2000 0.338 =2000# =100000 154 C500 0.164 514 79156 Values at OD 635 nm Glucose : 320 NA C300 0.152 NA NA 426 NA C400 0.170 NA NA 535 NA C550 0.184 NA NA Sample : Trizyme + Tea Nil C10000 6.00* > 10000# > 10000 50 C2000 0.305 =2000# =100000 154 C500 0. 147 441 67914 ---------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 36:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 1,36, 608 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 200,000 to 220,000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 173983 and 172649 mg/L, respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.78 = COD value (Merck Method) or our COD value (at OD 635) x 0.79 = COD value (Merck Method).
Hence for a preliminary estimate of COD value, color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference.
For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 36: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0. 161 NA NA 426 NA C400 0.187 NA NA 535 NA C550 0.202 NA NA Sample : Tea Nil C10000 6.00* > 10000# > 10000 20 C10000 1.648 > 10000# =200000 200 C1100 0.216 =1100# =220000 333.3 C500 0.164 522 173983 Values at OD 635 nm Glucose : 320 NA C300 0.144 NA NA 426 NA C400 0.167 NA NA 535 NA C550 0.184 NA NA Sample : Tea Nil C10000 6.00* > 10000# > 10000 20 C10000 1.531 > 10000# = 200000 200 C1100 0. 196-1100# =220000 333. 3 C500 0. 148 518 172649 ------------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 37:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (as such) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 6210 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 4000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 4270 mg/l and 3370mg/l. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.45 = COD value (Merck Method). or our COD value (at OD 635) x1. 84=COD (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 37: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.165 NA NA 426 NA C400 0.193 NA NA 535 NA C550 0.213 NA NA Sample : Damaged wheat grain (as such) Nil C1100 0. 491-1100 =1100# 10 C400 0.154 427 4270 Values at OD 635 nm Glucose : 320 NA C300 0.148 NA NA 426 NA C400 0.172 NA NA 535 NA C550 0.191 NA NA Sample : Damaged wheat grain (as such) Nil C1100 0.401 #1100 #1100# 10 C400 0. 130 337 3370 ------------------------------ # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 38:
Dissolved 0.3 g glucose in 50 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 4710.4 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 4800 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 5220 and 4998 mg/i respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.90 = COD value (Merck Method) or our COD value (at OD 635) x 0.94 = COD (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 38: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.163 NA NA 426 NA C400 0.176 NA NA 535 NA C550 0.226 NA NA Sample : Damaged wheat grain (ssp) Nil C1500 0.652 1500 #1500 10 C200 0.187 224 =2240# 12 C400 0.147 435 5220 Values at OD 635 nm Glucose : 320 NA C300 0.146 NA NA 426 NA C400 0.159 NA NA 535 NA C550 0.205 NA NA Sample : Damaged wheat grain (ssp) Nil C1500 0.551 1500 =1500 10 C200 0.168 224 # 2240# 12 C400 0. 127 416 4998 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 39:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Palm oil mill effluent (as such) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 15,801 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 12000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 13389 and 13506 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value at (OD 585) x 1.18 =
COD value (Merck Method) or our COD value (at OD 635) x 1.17 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 39: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.165 NA NA 426 NA C400 0.193 NA NA 535 NA C550 0.213 NA NA Sample : Palm oil Mill effluent (as such) Nil C10000- > 10, 000 > 10,000 10 C1900 0. 394-1900 =19, 000# 30 C400 0.165 446.3 13389 Values at OD 635 nm Glucose : 320 NA C300 0.148 NA NA 426 NA C400 0.172 NA NA 535 NA C550 0.191 NA NA Sample : Palm oil Mill effluent (as such) Ni ! C10000- > 10000 > 10000 10 C1900 0.360 # 1900 #19000# 30 C400 0. 148 450. 2 13506 ------------------------------------------------------------------------------------------ # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 40:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Palm oil mill effluent (ssp) was taken.
Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the
COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 1129.6 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 800 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 970 and 950 mg/l respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.16 = COD value (Merck Method) or our COD value (at OD 635) x 1.19 = COD value (Merck
Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 40: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 12 3456 Values at OD 585 nm Glucose : 320 NA C300 0.163 NA NA 426 NA C400 0.176 NA NA 535 NA C550 0.226 NA NA Sample : Palm oil Mill effluent (ssp) Nil C1500 0.263 =1500 =1500# 2 C400 0.171 485 970 Values at OD 635 nm Glucose: 320 NA C300 0.146 NA NA 426 NA C400 0.159 NA NA 535 NA C550 0.205 NA NA Sample : Palm oil Mill effluent (ssp) Nil C1500 0.242 #1500 #1500# 2 C400 0. 152 475 950 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 41:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain and POME (as such) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and
OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 9706 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 9000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 7660 and 7567 mg/l respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.27 = COD value (Merck Method) or our COD value (at OD 635) x 1.12.
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 41: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.165 NA NA 426 NA C400 0.193 NA NA 535 NA C550 0.213 NA NA Sample : DWS (S3) + POME (as such) Nil C10000 1.231 > 10,000 > 10, 000 10 C1500 0. 256 =1500 =15, 000 20 C450 0.186 =450 =9000 # 25 C300 0.132 306.4 7660 Values at OD 635 nm Glucose : 320 NA C300 0.148 NA NA 426 NA C400 0.172 NA NA 535 NA C550 0.191 NA NA Sample : DWS (S3) + POME (as such) Nil C10000 0.994 10,000 > 10,000 10 C1500 0.221 =1500 =15, 000 20 C450 0.165 =450 =9000 # 25 C300 0. 117 302. 6 7567 ---------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 42:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain and POME (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and
OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 4427.5 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 4000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 4068 and 3936 mg/ ! respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.09 = COD value (Merck Method) or our COD value (at OD 635) x 1.12.
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
DWS (S3) + POME (ssp)
Table 42: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.165 NA NA 426 NA C400 0.193 NA NA 535 NA C550 0.213 NA NA Sample : DWS (S3) + POME (ssp) Nil C1500 0.520 > 1500 > 1500 10 C400 0. 185 =400 =4000# 12 C300 0.146 339 4068 Values at OD 635 nm Glucose : 320 NA C300 0.148 NA NA 426 NA C400 0.172 NA NA 535 NA C550 0.191 NA NA Sample : DWS (S3) + POME (ssp) Nil C1500 0.427 > 1500 > 1500 10 C400 0.165 #400 #4000# 12 C300 0. 127 328 3936 -------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 43:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea (as such) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 74,589 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 90000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 101750 and 102000 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value at (OD 585 or OD 635) x 0.73 = COD value (Merck Method).
Hence, for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Tea (as such)
Table 43: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.223 NA NA Sample : TEA (as such) Nil C10000- > 10, 000 > 10,000 10 C10000- > 10, 000 > 1, 00,000 100 C1900 0.267 #1900 #1,90,000 111.1 C1300 0.245 =1300 =1, 44,430 166.7 C500 0.206 =550 =91, 685 200 C400 0.175 #450 #90,000# 250 C300 0.145 407 101750 Values at OD 635 nm Glucose : 320 NA C300 0.141 NA NA 426 NA C400 0.164 NA NA 535 NA C550 0.198 NA NA Sample : TEA (as such) Nil C10000- > 10, 000 > 10,000 10 C10000- > 10, 000 > 1,00, 000 100 C1900 0.237 #1900 #1,90,000 111.1 C1300 0.214 =1300 =1, 44,430 166.7 C500 0.182 =550 =91, 685 200 C400 0.155 =450 =90, 000# 250 C300 0. 128 408 102000 --------------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 44:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 67,528 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 75015 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 81380 and 18380 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585 or OD 635) x 0.83 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Tea (ssp)
Table 44: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose: 320 NA C300 0.159 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.223 NA NA Sample : TEA (ssp) Nil C10000- > 10, 000 = > 10, 000 10 C10000- > 10, 000 > 1,00, 000 100 C1800 0.244 =1800 =1, 80,000 125 C550 0. 222-550 =68, 750 166.7 C450 0.173 #450 #75,015# 200 C300 0.145 407 81380 Values at 00 635 nm Glucose : 320 NA C300 0.141 NA NA 426 NA C400 0.164 NA NA 535 NA C550 0.198 NA NA Sample: TEA (ssp) Nil C10000- > 10, 000 = > 10, 000 10 C10000- > 10, 000 > 1, 00,000 100 C1800 0.216 =1800 =1, 80,000 125 C550 0.190 =550 =68, 750 166.7 C450 0.152 =450 =75, 015# 200 C300 0. 128 408 81700 ----------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 45:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Apple pomace (ssp) was taken.
Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the
COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 39,284 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 30760 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 43000 and 43500 mg/i respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.91 =
COD value (Merck Method) or our COD value (at OD 635) x 435 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Apple Pomace (ssp)
Table 45: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.187 NA NA 535 NA C550 0.210 NA NA Sample : APPLE POMACE (ssp) Nil C10000- > 10, 000 > 10, 000 10 C1600 0.392 =1600 =16, 000 16.7 C800 0.354 =800 =13, 360 50 C550 0. 244 =550 =27, 500 76.9 C400 0.178 #400 #30,760# 100 C300 0.154 430 43000 Values at OD 635 nm Glucose : 320 NA C300 0.141 NA NA 426 NA C400 0.167 NA NA 535 NA C550 0.191 NA NA Sample : APPLE POMACE (ssp) Nil C10000- > 10, 000 > 10,000 10 C1600 0.336 =1600 =16, 000 16.7 C800 0.317 =800 =13, 360 50 C550 0.217 =550 =27, 500 76.9 C400 0.159 #400 #30,760# 100 C300 0. 139 435 45000 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 46:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea and Apple pomace (as such) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 56,948 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 40000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 68441 and 681334 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.83 =
COD value (Merck Method) or our COD value (at OD 635) x 0.84 = COD value (Merck Method).)
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Tea + Apple Pomace (as such)
Table 46: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.157 NA NA 426 NA C400 0.176 NA NA 535 NA C550 0.202 NA NA Sample: TEA + APPLE POMACE (as such) Nit C10000- > 10, 000 > 10,000 10 C1500 0.603 #1500 #15 000 50 C700 0.295 #700 #35,000 100 C400 0. 187-400 =40, 000# 153.8 C450 0.150 445 68441 Values at OD 635 nm Glucose : 320 NA C300 0.142 NA NA 426 NA C400 0.155 NA NA 535 NA C550 0.182 NA NA Sample : TEA + APPLE POMACE (as such) Nil C10000- > 10, 000 > 10,000 10 C1500 0.465 # 1500 #15,000 50 C700 0.262 #700 #35,000 100 C400 0.168 #400 #40,000# 153. 8 C400 0. 122 443 68134 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 47:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea + Apple pomace (ssp) and POME was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 60,398 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 45000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 66,134 and 67,364 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.91 =
COD value (Merck Method) or our COD value (at OD 635) x 0.90 = COD value (Merck Method).)
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Tea + Apple Pomace (ssp)
Table 47: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.157 NA NA 426 NA C400 0.176 NA NA 535 NA C550 0.202 NA NA Sample : TEA + APPLE POMACE (ssp) Nil C10000- > 10, 000 > 10,000 10 C1400 0.621 =1400 =14, 000 50 C800 0.284 #800 #40,000 100 C450 0. 181 =450 =45, 000 153.8 C400 0.145 430 66,134 Values at OD 635 nm Glucose : 320 NA C300 0.142 NA NA 426 NA C400 0.155 NA NA 535 NA C550 0.182 NA NA Sample: TEA + APPLE POMACE (ssp) Nil C10000- > 10, 000 > 10, 000 10 C1400 0. 473 =1400 =14, 000 50 C800 0.284 =800 =40, 000 100 C450 0.159 #450 #45,000 153.8 C400 0.130 438 67,364 ------------------------------------------------------------------------------------------------ # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 48:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Digested POME (as such) was taken.
Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the
COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 5993.8 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 1700 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 3120 and 3160 mg/l respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.92 = COD value (Merck Method) or our COD value (at OD 635) x 1.90 = COD value (Merck Method).) Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Digested POME (as such)
Table 48: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.162 NA NA 426 NA C400 0.189 NA NA 535 NA C550 0.207 NA NA Sample : Digested POME (as such) Nil C1700 1.021 =1700 =1700# 10 C250 0.132 312 3120 Values at OD 635 nm Glucose : 320 NA C300 0.146 NA NA 426 NA C400 0.171 NA NA 535 NA C300 0.187 NA NA Sample : Digested POME (as such) Nil C1700 0.889 =1700-1700# 10 C250 0. 120 316 3160 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
** : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 49:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Digested POME (ssp) was taken.
Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the
COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to
OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 588.4 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 400 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 535 and 458 mg/l respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.10 = COD value (Merck Method) or our COD value (at OD 635) x 1.30 = COD value (Merck
Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Digested POME (ssp)
Table 49: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.162 NA NA 426 NA C400 0.189 NA NA 535 NA C550 0.207 NA NA Sample : Digested POME (ssp) Nil C400 0.168 535 535 Values at OD 635 nm Glucose : 320 NA C300 0.146 NA NA 426 NA C400 0.171 NA NA 535 NA C550 0.187 NA NA Sample : Digested POME (ssp) Ni ! C400 0. 148 458 458 ----------------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an CD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 50 :
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Digested POME and Tea (as such) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 59,593 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 50000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 41600 and 41900 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1. 43 = COD value (Merck Method) or our COD value (at OD 635) x 1.42 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Digested Pome + Tea (as such)
Table 50: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.162 NA NA 426 NA C400 0.187 NA NA 535 NA C550 0.208 NA NA Sample: Digested Pome + Tea (as such) Nil C10000- > 10, 000 > 10, 000 10 C5000 0. 416 ==5000 =50, 000# 100 C400 0.149 416 41600 Values at OD 635 nm Glucose : 320 NA C300 0.141 NA NA 426 NA C400 0.162 NA NA 535 NA C500 0.192 NA NA Sample : Digested Pome + Tea (as such) Nil C10000- > 10, 000 > 10,000 10 C5000 0. 353 =5000 =50, 000# 100 C400 0. 130 419 41900 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 51:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Digested POME and Tea (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 39,928 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 20000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 38556 and 36985 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.43 =
COD value (Merck Method) or our COD value (at OD 635) x 1.42 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Digested Pome + Tea (ssp)
Table 51: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.162 NA NA 426 NA C400 0.187 NA NA 535 NA C550 0.208 NA NA Sample : Digested Pome + Tea (ssp) Nil C10000- > 10, 000 =10, 000 10 C2000 0. 386 ==2000 =20, 000# 100 C200 0.107 200 20,000 71.4 C500 0.175 540 38556 Values at OD 635 nm Glucose : 320 NA C300 0.141 NA NA 426 NA C400 0.162 NA NA 535 NA C550 0.192 NA NA Sample: Digested Pome + Tea (ssp) Nil C10000- > 10, 000 =10, 000 10 C2000 0.336 =2000 =20, 000# 100 C200 0.092 200 20,000 71. 4 C500 0. 155 518 36985 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 52:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Digested POME and Apple pomace (as such) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and
OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 24,932 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 15000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 15800 and16955 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.58 =
COD value (Merck Method) or our COD value (at OD 635) x 1.47 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Digested Pome + Apple Pomace (as such)
Table 52: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 12 3456 Values at OD 585 nm Glucose : 320 NA C300 0.158 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.205 NA NA Sample : Digested Pome + Apple Pomace (as such) Nil C10000- > 10, 000 > 10,000 10 C1500 0.336 =1500 =15, 000# 50 C400 0.130 316 15800 Values at OD 635 nm Glucose : 320 NA C300 0.137 NA NA 426 NA C400 0.159 NA NA 535 NA C550 0.191 NA NA Sample : Digested Pome + Apple Pomace (as such) Nil C10000- > 10, 000 > 10, 000 10 C1500 0.305 1500 =15, 000# 50 C400 0. 121 339 16955 ----------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D: Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 53:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Digested Palm oil mill effluent (POME) and Apple pomace (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 21,666 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 16000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 32600 and 41310 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.66 =
COD value (Merck Method) or our COD value (at OD 635) x 0.52 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Digested Pome + Apple Pomace (ssp)
Table 53: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.158 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.205 NA NA Sample : Digested Pome + Apple Pomace (ssp) Nil C10000 - > 10,000 > 10,000 10 C1600 0.357 =1600 =16. 000# 100 C300 0.134 326 32600 Values at OD 635 nm Glucose : 320 NA C300 0.137 NA NA 426 NA C400 0.159 NA NA 535 NA C550 0.191 NA NA Sample : Digested Pome + Apple Pomace (ssp) Nil C10000 - > 10,000 > 10,000 10 C1600 0.357 #1600 #16. 000# 100 C300 0. 134 413 41300 ------------------------------------------------------------------------------------ # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 54:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Digested POME, Apple pomace and
Tea (as such) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 34,569 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 45000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 35774 and 36552 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.97 =
COD value (Merck Method) or our COD value (at OD 635) x 0.94 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Digested Pome + Apple Pomace + Tea (as such)
Table 54: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.160 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.211 NA NA Sample : Digested Pome + Apple Pomace + Tea (as such) Nil C10000- > 10, 000 > 10, 000 10 C4500 0.428 #4500 #45,000# 100 C450 0. 189 =450 =45, 000# 111.1 C300 0.134 322 35774 Values at OD 635 nm Glucose : 320 NA C300 0.141 NA NA 426 NA C400 0.162 NA NA 535 NA C550 0.197 NA NA Sample : Digested Pome + Apple Pomace + Tea (as such) Nil C10000- > 10, 000 > 10,000 10 C4500 0.375 #4500 #45,000# 100 C450 0.173 #450 #45,000# 111. 1 C300 0. 121 329 36552 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 55:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Digested POME, Apple pomace and
Tea (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2CrOy was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and
OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 34,040 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 40000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 46800 and 48100 mg/l. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.73 = COD value (Merck Method) or our COD value (at OD 635) x 0.71 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Digested Pome + Apple Pomace + Tea (ssp)
Table 55: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.160 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.211 NA NA Sample : Digested Pome + Apple Pomace + Tea (ssp) Nil C10000- > 10, 000 > 10,000 10 C4000 0.373 =4000 =40, 000# 100 C400 0.166 468 46800 Values at OD 635 nm Glucose: 320 NA C300 0.141 NA NA 426 NA C400 0.162 NA NA 535 NA C550 0.197 NA NA Sample : Digested Pome + Apple Pomace + Tea (ssp) Nil C10000- > 10,000 > 10,000 10 C4000 0.322 #4000 #40 000# 100 C400 0. 149 481 48100 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 56:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea and Apple pomace (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 75,716 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 78540 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 86400 and 83600 mg/ ! respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 0.88 =
COD value (Merck Method) or our COD value (at OD 635) x 0. 91 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Tea + Apple Pomace (ssp)
Table 56: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.205 NA NA Sample : Tea + Apple Pomace (ssp) Nil C10000- > 10, 000 = > 10, 000 10 C5500 0.372 #500 #55,000 100 C1600 0. 225 =1600 =1, 60,000 142.8 C550 0.175 =550 =78, 540# 200 C400 0.157 432 86400 Values at OD 635 nm Glucose : 320 NA C300 0.143 NA NA 426 NA C400 0.168 NA NA 535 NA C550 0.186 NA NA Sample: Tea + Apple Pomace (ssp) Nil C10000- > 10, 000 = > 10, 000 10 C5500 0.295 #5500 # 55,000 100 C1600 0.201 =1600 =1, 60,000 142.8 C550 0.155 #550 #78,540# 200 C400 0. 136 418 83600 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 57:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 11,707 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 1400 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 5160 and 5040 mgll respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 2.26 = COD value (Merck Method) or our COD value (at OD 635) x 2.31 = COD value (Merck
Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
DWS (S3) (ssp)
Table 57: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.186 NA NA 535 NA C550 0.205 NA NA Sample : DWS (S3) (ssp) Nil C1400 0.636 #1400 #1400# 10 C400 0.165 516 5160 Values at OD 635 nm Glucose : 320 NA C300 0.143 NA NA 426 NA C400 0.168 NA NA 535 NA C550 0.186 NA NA Sample : DWS (S3) (ssp) Nil C1400 0.494 #1400 #1400# 10 C400 0. 147 504 5040 ----------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 58:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea, Apple pomace and Damaged wheat grain (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes.
1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 22,689. 5 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 20000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 22450 and 16950 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 2.26 =
COD value (Merck Method) or our COD value (at OD 635) x 2.31 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Tea + Apple Pomace + DWS (S3) (ssp)
Table 58: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.161 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.209 NA NA Sample : Tea + Apple Pomace + DWS (S3) (ssp) Nil C10000- > 10, 000 > 10,000 10 C4000 0.356 #4000 #40,000 66.7 C300 0.127 #300 #20,000# 50 C400 0.162 449 22450 Values at OD 635 nm Glucose : 320 NA C300 0.142 NA NA 426 NA C400 0.163 NA NA 535 NA C550 0.198 NA NA Sample : Tea + Apple Pomace + DWS (S3) (ssp) Nil C10000- > 10, 000 > 10,000 10 C4000 0.319 #4000 #40,000 66.7 C300 0.113 #300 #20,000# 50 C400 0. 142 339 16950 ---------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 59:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea, Apple pomace, Damaged wheat grain and Peptone (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 36,176 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 20000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 20900 and 21050 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.73 =
COD value (Merck Method) or our COD value (at OD 635) x 1.72 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Tea + Apple Pomace + DWS (S3) + Peptone (ssp)
Table 59: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.161 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.209 NA NA Sample : Tea + Apple Pomace + DWS (S3) + Peptone (ssp) Nil C10000- > 10, 000 > 10,000 10 C2000 0.348 #2000 #20,000# 50 C300 0.151 418 20900 Values at OD 635 nm Glucose : 320 NA C300 0.142 NA NA 426 NA C400 0.163 NA NA 535 NA C550 0.198 NA NA Sample : Tea + Apple Pomace + DWS (S3) + Peptone (ssp) Nil C10000- > 10, 000 > 10, 000 10 C20000 0. 315 ==2000 =20, 000# 50 C300 0. 134 421 21050 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
* : OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 60:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea, Apple Pomace and Dabu (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 77,786 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 55000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 71714 and 74348 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.08 =
COD value (Merck Method) or our COD value (at OD 635) x 1.05 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Tea + Apple Pomace + Dabu (ssp)
Table 60: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.187 NA NA 535 NA C550 0.206 NA NA Sample: Tea + Apple Pomace + Dabu (ssp) Ni ! C10000- > 10, 000 > 10, 000 10 C5000--5000-50, 000 100 C550 0.216 =550 =55, 000# 166.7 C400 0.157 430 71681 Values at OD 635 nm Glucose : 320 NA C300 0.141 NA NA 426 NA C400 0.162 NA NA 535 NA C550 0.195 NA NA Sample : Tea + Apple Pomace + Dabu (ssp) Nil C10000- > 10, 000 > 10, 000 10 C5000- #5000 #50,000 100 C550 0. 195 =550 =55, 000# 166. 7 C400 0. 141 446 74348 --------------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 61:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain and Dabu (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 65,251 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 45000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 63625 and 58000 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.02 =
COD value (Merck Method) or our COD value (at OD 635) x 1.12 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
DWS (S3) + Dabu (ssp)
Table 61: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.187 NA NA 535 NA C550 0.206 NA NA Sample: DWS (S3) + Dabu (ssp) Nil C5500-5500 =5500 10 C4000-4000 =40, 000 100 C450 0.168 450 #45,000# 125 C300 0.163 509 63625 Values at OD 635 nm Glucose : 320 NA C300 0.141 NA NA 426 NA C400 0.162 NA NA 535 NA C550 0.195 NA NA Sample : DWS (S3) + Dabu (ssp) Nil C5500-5500 5500 10 C4000 - 4000 #40,000 100 C450 0.150 450 =45, 000# 125 C300 0. 145 464 58000 --------------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 62:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea, Apple Pomace, Damaged wheat grain and NaCI (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 27,163 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 10000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 16300 and 17450 mg/i respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.67 =
COD value (Merck Method) or our COD value (at OD 635) x 1.56 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Table 62: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.158 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.207 NA NA Sample : Tea + Apple Pomace + DWS (S3) + NaCI (ssp) Nil C10000- #10,000 #10,000# 50 C300 0.134 326 16300 66.7 C300 0.112 300 20,010 Values at OD 635 nm Glucose : 320 NA C300 0.132 NA NA 426 NA C400 0.160 NA NA 535 NA C550 0.195 NA NA Sample : Tea + Apple Pomace + DWS (S3) + NaCI (ssp) Nil C10000- #10,000 #10,000# 50 C300 0.120 349 17450 66. 7 C300 0. 099 300 20, 010 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 63:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea, Apple Pomace, Damaged wheat grain and Glucose (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 53,866 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 50000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 517000 and 41600 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.04 =
COD value (Merck Method) or our COD value (at OD 635) x 1.30 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Tea + Apple Pomace + DWS (S3) + Glucose (ssp)
Table 63: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.158 NA NA 426 NA C400 0.185 NA NA 535 NA C550 0.207 NA NA Sample : Tea + Apple Pomace + DWS (S3) + Glucose (ssp) Ni ! C10000- > 10, 000 > 10000 10 C5000-5000 50, 000# 100 C500 0.167 517 51700 Values at OD 635 nm Glucose : 320 NA C300 0.132 NA NA 426 NA C400 0.160 NA NA 535 NA C550 0.195 NA NA Sample : Tea + Apple Pomace + DWS (S3) + Glucose (ssp) Nil C10000- > 10, 000 > 10000 10 C5000-5000 50, 000# 100 C400 0. 150 416 41600 -------------------------------------------------------------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
EXAMPLE 64:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Damaged wheat grain (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically. OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 6649.3 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 500 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 5260and 5190 mg/l respectively. A comparison with the COD value calculated through Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.26 = COD value (Merck Method) or our COD value (at OD 635) x 1.30 = COD value (Merck
Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
DWS (S3) (ssp)
Table 64: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.187 NA NA 535 NA C550 0.210 NA NA Sample : DWS (S3) (ssp) Nil C550-550 550# 10 C400 0.172 526 5260 Values at OD 635 nm Glucose : 320 NA C300 0.142 NA NA 426 NA C400 0.167 NA NA 535 NA C550 0.189 NA NA Sample : Digested POME (ssp) Nil C550-550 550# 10 C400 0. 151 531 5310 -------------------------------------------- # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in Examples 3 to 15).
EXAMPLE 65:
Dissolved 0.15 g glucose in 25 mL distilled water. Aliquots from the stock solution were taken and diluted with water to achieve different COD concentrations in the range of 320 to 535 mg/L. A 30 mL sample of Tea, Apple Pomace, Damaged wheat grain and Glucose (ssp) was taken. Weighed 0.02 g HgS04 in separate 15 mL test tubes. 1.0 mL of glucose solution and sample were added to each test tube separately and mixed well. 0.5 mL of K2Cr207 was added to each sample. 1.5 mL H2SO4 silver sulphate reagent was added slowly with continuous shaking. The color of the reaction mixture was noted down visually within 15 sec of incubation and also recorded spectrophotometrically at 585 and 635 nm against air. An approximate
COD value of the sample was estimated from the color of standard reaction mixture prepared with glucose as reference material in the COD range of 200 to 100000 mg/L. OD 585 and OD 635 of the reaction mixture was read spectrophotometrically.
OD 585 and 635 nm in the range of 0.130 to 0.175 and 0.120 to 0.160 respectively were considered and calculated with reference to glucose standard. (Glucose COD in the range of 320 to 535 mg/L corresponds to OD 585 and 635 nm in the range of 0.157 to 0.207 and 0.142 to 0.189, respectively).
COD of the sample was estimated to be 30,866 mg/L. (By Merck method and read on photometer).
Based on the color of the reaction mixture, COD of the sample was estimated to be around 20000 mg/L. On the basis of the dilution method and the spectrophotometric reading at OD 585 and OD 635 of the sample, COD was estimated to be 20,850 and 20,450 mg/l respectively. A comparison with the COD value calculated through
Merck method reveals the following relation i. e. Our COD value (at OD 585) x 1.48 =
COD value (Merck Method) or our COD value (at OD 635) x 1.51 = COD value (Merck Method).
Hence for a preliminary estimate of COD value color of the standard reaction mixture based on a range of glucose concentrations can be used as a reference. For samples, with COD concentration of 300 to 500 mg/L, OD 585 or OD 635 can be recorded for obtaining more precise values.
Tea + Apple Pomace + DWS (S3) + Glucose (ssp)
Table 65: Correlation between COD concentration, color of the reaction mixture and their OD at different wave lengths.
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COD Sample Color of the OD Estimated Estimated (mg/L) dilution reaction COD final COD (Times) mixture (mg/L) (mg/L) (Col. 2x5) 1 2 3 4 5 6 Values at OD 585 nm Glucose : 320 NA C300 0.159 NA NA 426 NA C400 0.187 NA NA 535 NA C550 0.210 NA NA Sample : Tea + Apple Pomace + DWS (S3) + Glucose (ssp) Ni ! C10000- > 10, 000 10 C2000 0.359 2000 20, 000# 50 C400 0.152 417 20,850 Values at OD 635 nm Glucose : 320 NA C300 0.142 NA NA 426 NA C400 0.167 NA NA 535 NA C550 0.189 NA NA Sample : Tea + Apple Pomace + DWS (S3) + Glucose (ssp) Nil C10000- > 10, 000 10 C2000 0.359 2000 20, 000# 50 C400 0. 152 409 20, 450 # : COD as deducible from Table 2 given in Example 2. D : Dark. T: Turbid.
*: OD out of range. NA: Not applicable. Samples are diluted to get an OD 585 in the range of 0.130 to 0.175 and OD 635 in the range of 0.120 to 0.160, to obtain a
COD value in the range of 320 to 535 mg/L. (Based on the Tables 3 to 15 given in
Examples 3 to 15).
The main advantages of the present invention are 1. The test can be carried out rapidly.
2. The test does not require any major instrument.
3. The test is very cheap.
4. The test requires very small amount of reagents.
5. The test is easy to perform.
6. The test can be done without the need for specially trained technician.
7. The test can be performed with the help of a kit also.
Claims (49)
- Claims 1. A method for the preparation of COD chart useful for the estimation of COD in a sample, said method comprising the steps of: a) preparing a standard glucose solution by dissolving glucose in purified, preferably distilled water at a concentration ranging between 200 mg/L to 1,00, 000 mg/L with a COD concentration ranging between 213 mg/L to 1,06, 700 mg/L, b) mixing a portion of volume X of standard glucose solutions from step (a), individually, with three reagents, consisting of 0.02 g mercuric sulfate per mL of standard glucose solution, 0.5 mL of 0.25 N potassium dichromate solution or equivalent molar quantity per mL of standard glucose solution and 1.5 mL of sulfuric acid-silver sulfate per mL of standard glucose solution in a sequential manner, and c) preparing a COD color chart of different glucose concentration based on the COD concentration ranging between 213 mg/L to 1,06, 700 mg/L, and which chart is useful for rough estimation of COD values by comparing the colors of the chart with the color of the samples.
- 2. A rapid method for the estimation of COD of an effluent from domestic, industrial, municipal and other sources, said method comprising the steps of a) preparing a set of standard glucose solutions by dissolving glucose in purified, preferably distilled water at a concentration ranging between 300 mg/L to 500 mg/L, with a COD concentration of 320 mg/L to 535 mg/L, b) mixing a portion of volume X of standard glucose solutions from step (a), individually, with three reagents, consisting of 0.02 g mercuric sulfate per mL of standard glucose solution, 0.5 mL of 0.25 N potassium dichromate solution or equivalent molar quantity per mL of standard glucose solution and 1.5 mL of sulfuric acid-silver sulfate per mL of standard glucose solution in a sequential manner, and c) mixing a portion of volume X of a sample to be tested with 0.01 to 0.03g mercuric sulfate per mL of standard glucose solution, 0.5 mL of 0.25 N to 0.30 N potassium dichromate solution or equivalent molar quantity per mL of standard glucose solution and 1.5 mL of sulfuric acid-silver sulfate per mL of standard glucose solution in a sequential manner, and noting down the color and if the color of the reaction mixture turns (color code C10000) brown, d) diluting the sample according to tables, for example 1 (a), with purified, preferably distilled water, till a particular color range of C100 to C10000 is achieved, for example as shown in Figure 1 of the accompanying drawing, e) further diluting the sample with purified, preferably distilled water to obtain a COD range in between 320 to 535 mg/L wherein the dilution is determined according to colour tables, for example, 1 (a) & (b), f) mixing a portion of volume X of diluted sample from step (e), individually, with three reagents, consisting of 0. 01 g to 0. 03g mercuric sulfate per mL of standard glucose solution, 0.5 mL of 0.25 N to 0.30 N potassium dichromate solution or equivalent molar quantity per mL of standard glucose solution and1.5 mL of sulfuric acid-silver sulfate per mL of standard glucose solution in a sequential manner, and g) matching the color of the reaction mixture of the above sample (step f) with a COD color chart provided, for example, in Figure 1 of the accompanying drawing, h) noting the optical density (OD) of the reaction mixture of standard glucose solutions (step b) and sample (step f) at 585 nm or 635 nm, against air, i) drawing a correlation between the OD values of above sample with OD values of standard glucose solutions, j) multiplying the OD value of sample (step h) with a correction factor of 1.2, comparing this value (A) with the OD value of standard glucose solution of COD value 320 to 535 mg/l, k) multiplying value (A) with the compared COD value of standard Glucose solution and divided by the respective OD value of the glucose standard (B) and 1) then multiply value (B) with a dilution factor (in case of diluted sample) to obtain the COD value of the sample in terms of, for example, mg/l.
- 3. A method as claimed in claim 2 wherein, the Dilution Factor is the total volume used divided by volume of the sample.
- 4. A method as claimed in claim 2 wherein, the effluent used is selected from domestic, industrial, municipal, agricultural and other waste material sources.
- 5. A method as claimed in claim 2 wherein, the waste material is in the form of solid, liquid, semi-solid or viscous forms.
- 6. A method as claimed in claim 2 wherein, the volume of the test sample or standard solution ranges from 20 to 100 mi.
- 7. A method as claimed in claim 2 wherein, the incubation is carried out for a period in the range of 15 seconds to 1 minute.
- 8. A method as claimed in claim 2 wherein, the COD is estimated in the range between 80 to 106700 mg/L.
- 9. A method as claimed in claim 2 wherein, the glucose concentration is tested in the range between 50 to 100000 mg/L.
- 10. A method as claimed in claim 2 wherein, the HgS04 used in the test samples is 0.02g.
- 11. A method as claimed in claim 2 wherein, the K2Cr207 used in the test samples is 0.25 Normal.
- 12. A method as claimed in claim 2 wherein, the H2SO4-silver sulfate reagent used in the test samples is 1.5 mL.
- 13. A method as claimed in claim 2 wherein, the COD color chart is applicable for the COD values in the range of 100 to 10,000 mg/L.
- 14. A method as claimed in claim 2 wherein, the test samples of COD more than 10000 mg/L is diluted appropriately,
- 15. A method as claimed in claim 2 wherein, the O. D of the sample is read at the wavelengths 585 and 635 nm.
- 16. A method as claimed in claim 2 wherein, the optical density readings are measured for the COD values ranging from 320 to 535 mg/L.
- 17. A method as claimed in claim 2 wherein, the sample is in the form of slurry.
- 18. A method as claimed in claim 2 wherein, the test sample comprises of agricultural waste, municipal market waste, fruit and food industry waste, beverages, chemicals, microbes and animal waste etc.
- 19. A method as claimed in claim 2 wherein, the tables 1 (a) and 1 (b) are as follows :Table 1 (a)Color of the Required dilution Color code Expected COD of unknown reaction of sample sample (mg/L) mixture C 10000 10 C1000 10000 C 10000'100C100-C50010000-50000 C 10000 200 C250-C500 50000-100000 C 10000 500 C200-C2000100000-1000000Table 1 (b)Color of the reaction Expected COD Dilution required to bring COD mixture (mg/L) value (300-500 mg/L) C9000 9000-9500 18-31 C6000 6000-8500 12-28 C2000 2000-5500 4-18 C1500 1500-1900 3-6 C1200 1200-1400 2-5 C600 600-1100 2-4 C500 500-550 NIL C400 400-450 NIL C300 300-350 NIL C200 200-250 NIL C150 100-150 NIL C10000-100'NtL
- 20. A method as claimed in claim 2 wherein, in step (d) the dilution of samples, provide dark brown reaction mixture, falling in the range of 10 to 500 for approximate COD values of 10000 mg/l and above as given in Table1 (c) and further dilution of 0 to 31 is done to bring the COD in the range of 300 to 500 mgll as given in Table 1 (d).
- 21. A method as claimed in claim 2 wherein, in step (e), the samples provide yellowish to blackish brown colored reaction mixture falling in the range of 100 to 9500 mg/l COD and the samples are further diluted nil to 31 times to obtain a diluted sample in the COD range of 300 to 500 mg/), according to the Table 1 (d).
- 22. A method as claimed in claim 2 wherein, in step (d) the dilution of samples and color groups range from (A) to (G) for approximate COD values lying in the range of 100 to 9500 mg/l as given in table 1 (d)
- 23. A method as claimed in claim 20 wherein, tables 1 (c) and 1 (d) are as shown below.TABLE 1 (c)Color of the Color code Dilution Color obtained Expected Expected COD of reaction of the required to on dilution as COD of the unknown sample mixture reaction bring the per the provided reaction (mgll) mixture as COD values color chart mixture (mg/1) per the in the range provided of 100chart 1000 mg/l ix) 10 C 1000 1000 10000 C 10000 to x) 100 C 100-C500 100 to 500 10000 to 50000 Dark brown C 100000 xi) 200 C 250-C 500 250 to 500 50000 to 100000 xii) 500 C 200 to C 2000 200 to 2000 100000 to 1000000 Table 1 (d) Color Color of the Color code of the Expected COD Dilution required to bring group reaction reaction mixture as per of the reaction the COD values In the mixture the chart provided mixture range of 300 to 500 mg/l A Yellowish C 100 to C 250 1 to 250 Nil B Yellowish C 300 to C 550 300 to 550 Nil Greenish blue C 600 to C 1000 600 to 1000 2 to 4 Blue to grayish C 1500 to C 2500 1500 to 2500 3 to 6blue E Dirty brown C 3000 to C 5500 3000 to 5500 6 to 18 F Cola brown C 6000 to C 8500 6000 to 8500 12 to 28 G Blackish brown C 9000 to 9500 9000 to 9500 18-31
- 24. A kit for estimation of Chemical Oxygen Demand (COD) which comprises: a) reagents A) HgS04 (solid), B) Glucose standard solutions ranging from 300 to 500 mg/L, C). K2Cr207 solution (0.25 to 0.3 N), and D) H2S04-sitver sulfate reagent, b) a glass vial, c) a photometric cell, d) a COD color chart as shown in fig 1 of the accompanying drawing and a photometer suitable for wave lengths in the range of 585 to 635 nm.
- 25. A method for the preparation of reference tables of the type 1 (e) and 1 (f) of COD values, useful for the estimation of COD in a sample, said method comprising the steps of: a) preparing standard glucose solution by dissolving glucose in purified, preferably distilled water at a concentration ranging between 200 mg/L to 1,00, 000 mg/L with a COD concentration ranging between 213 mg/L to 1,06, 700 mg/L, b) mixing a portion of volume X of standard glucose solutions from step (a), individually, with three reagents, consisting of 0.02 g mercuric sulfate per mL of standard glucose solution, 0.5 mL of 0.25 N potassium dichromate solution or equivalent molar quantity per mL of standard glucose solution and 1.5 mL of sulfuric acid-silver sulfate per mL of standard glucose solution in a sequential manner, and c) preparing reference tables of the type 1 (e) and 1 (f) for COD values of different glucose concentration based on the COD concentration ranging between 213 mg/L to 1,06, 700 mg/L, and which tables are useful for rough estimation of COD values by comparing the colors indicated in the tables with the color of the samples.
- 26. A method as claimed in claim 25 wherein, the reference tables 1 (e) and 1 (f) are as shown below.TABLE 1 (e)Color of the Dilution required to Expected COD of Expected COD of reaction bring the COD the reaction unknown sample (mg/1) mixture values in the range mixture (mg/1) of 100-1000 mg/l xiii) 10 1000 10000 xiv) 100 100 to 500 10000 to 50000 Dark brown xv) 200 250 to 500 50000 to 100000 xvi) 500 200 to 2000 100000 to 1000000 Table 1 (f) Color Color of the Expected COD of Dilution required to bring the COD group reaction mixture the reaction mixture values in the range of 300 to 500 mg/i A Yellowish 1 to 250 Nil Yellowish 300 to 550 Nil C Greenish blue 600 to 1000 2 to 4 Blue to grayish D 1500 to 2500 3 to 6 blue E Dirty brown 3000 to 5500 6 to 18 F Cola brown 6000 to 8500 12 to 28 G Blackish brown 9000 to 9500 18-31
- 27. A rapid method for the estimation of COD of an effluent from domestic, industrial, municipal and other sources, said method comprising the steps of a) preparing a set of standard glucose solutions by dissolving glucose in purified water, preferably distilled water at a concentration ranging between 300 mg/L to 500 mg/L, with a COD concentration of 320 mg/L to 535 mg/L, b) mixing a portion of volume X of standard glucose solutions from step (a), individually, with three reagents, consisting of 0.02 g mercuric sulfate per mL of standard glucose solution, 0.5 mL of 0.25 N potassium dichromate solution or equivalent molar quantity per mL of standard glucose solution and 1.5 mL of sulfuric acid-silver sulfate per mL of standard glucose solution in a sequential manner, c) mixing a portion of volume X of a sample to be tested with 0.01 g to 0.03 g mercuric sulfate per mL of standard glucose solution, 0.5 mL of 0.25 N to 0.30 N potassium dichromate solution or equivalent molar quantity per mL of standard glucose solution and 1.5 mL of sulfuric acid-silver sulfate per mL of standard glucose solution, in a sequential manner and noting down the color till the color of the reaction mixture turns brown, d) diluting the sample as per tables of the type 1 (e) and 1 (f) with purified, preferably distilled water till a particular color range shown in the tables is achieved, e) further diluting the sample with purified, preferably distilled water to obtain a COD range in between 320 to 535 mg/L wherein the dilution is determined according to tables of the type 1 (e) and 1 (f), f) mixing a portion of volume X of diluted sample from step (e), individually, with three reagents, consisting of 0.01 g to 0.03 g mercuric sulfate per mL of standard glucose solution, 0.5 mL of 0.25 N to 0.30 N potassium dichromate solution or equivalent molar quantity per mL of standard glucose solution and1.5 mL of sulfuric acid-silver sulfate per mL of standard glucose solution in a sequential manner, and, g) matching the color of the reaction mixture of the above sample (step f) with the COD color provided in tables of the type 1 (e) and 1 (f), h) noting the optical density (OD) of the reaction mixture of standard glucose solutions (step b) and sample (step f) at 585 nm or 635 nm, against air, i) drawing a correlation between the OD values of above sample with OD values of standard glucose solutions, j) multiplying the OD value of sample (step h) with a suitable correction factor, for example, 1.2, comparing this value (A) with the OD value of standard glucose solution of COD value 320 to 535 mg/l, k) multiplying value (A) with the compared COD value of standard Glucose solution and divided by the respective OD value of the glucose standard (B) and 1) then multiply value (B) with a dilution factor (in case of diluted sample) to obtain the COD value of the sample in terms of, for example, mg/l.
- 28. A method as claimed in claim 27 wherein, in step d, the dilution of samples provide dark brown reaction mixture falling in the range of 10 to 500 for approximate cod values of 10000 mg/l and above as given in Table type 1 (e) and further dilution of nil to 31 is done to bring the COD in the range of 300 to 500 mg/l as given in Table type 1 (f).
- 29. A method as claimed in claim 27 wherein, in step (e), the samples provide yellowish to blackish brown coloured reaction mixture falling in the range of 100to 9500 mg/l COD and the samples are further diluted to 31 times to obtain a diluted sample in the COD range of 300 to 500 mg/l, according to the Tables l (e) and 1 (f).
- 30. A method as claimed in claim 27 wherein, in step (d) the dilution of samples and color groups range from (A) to (G) for approximate COD values lying in the range of 100 to 9500 mg/l as given in table 1 (d)
- 31. A method as claimed in claim 27 wherein, the Dilution Factor is the total volume used divided by volume of the sample.
- 32. A method as claimed in claim 27 wherein, the effluent used is selected from domestic, industrial, municipal, agricultural and other waste material sources.
- 33. A method as claimed in claim 27 wherein, the waste material is in the form of solid, liquid, semi-solid or viscous forms.
- 34. A method as claimed in claim 27 wherein, the reagents comprising of HgS04, glucose standard solutions, K2Cr207 solution and H2SO4-silver sulfate reagent.
- 35. A method as claimed in claim 27 wherein, the volume of the test sample or standard solution ranges from 20 to 100 ml.
- 36. A method as claimed in claim 27 wherein, the incubation is carried out for a period in the range of 15 seconds to 1 minute.
- 37. A method as claimed in claim 27 wherein, the COD is estimated in the range between 80 to 106700 mg/L.
- 38. A method as claimed in claim 27 wherein, the glucose concentration is tested in the range between 50 to 100000 mg/L.
- 39. A method as claimed in claim 27 wherein, the HgS04 used in the test samples is 0.02 g.
- 40. A method as claimed in claim 27 wherein, the K2Cr207 used in the test samples is 0.25 Normal.
- 41. A method as claimed in claim 27 wherein, the H2SO4-silver sulfate reagent used in the test samples is 1.5 mL.
- 42. A method as claimed in claim 27 wherein, the COD color chart is applicable for the COD values in the range of 100 to 10,000 mg/L.
- 43. A method as claimed in claim 27 wherein, the test samples of COD more than 10000 mg/L is diluted appropriately,
- 44. A method as claimed in claim 27 wherein, the OD of the sample is read at the wavelengths 585 and 635 nm.
- 45. A method as claimed in claim 27 wherein, the optical density readings are measured for the COD values ranging from 320 to 535 mg/L.
- 46. A method as claimed in claim 27 wherein, the sample is in the form of slurry.
- 47. A method as claimed in claim 27 wherein, the test sample comprises of agricultural waste, municipal market waste, fruit and food industry waste, beverages, chemicals, microbes and animal waste etc.
- 48. A kit for estimation of Chemical Oxygen Demand (COD) which comprises: a) reagents A) HgS04 (solid), B) Glucose standard solutions ranging from 300 to 500 mg/L, C) K2Cr207 solution C) K2Cr207 solution (0.25 to 0.3 N) and D) H2SO4-silver sulfate reagent, b) a glass vial, c) a photometric cell, d) a COD reference tables 1 (e) and 1 (f), and e) a photometer suitable for wave lengths in the range of 585 to 635 nm.
- 49. A method according to any preceding claim wherein the portion X is 1 mL.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US09/820,538 US6967104B2 (en) | 2001-03-29 | 2001-03-29 | Rapid method for estimation of Chemical Oxygen Demand |
| GB0107869A GB2373855B (en) | 2001-03-29 | 2001-03-29 | A rapid method for estimation of chemical oxygen demand |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US09/820,538 US6967104B2 (en) | 2001-03-29 | 2001-03-29 | Rapid method for estimation of Chemical Oxygen Demand |
| GB0107869A GB2373855B (en) | 2001-03-29 | 2001-03-29 | A rapid method for estimation of chemical oxygen demand |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0107869D0 GB0107869D0 (en) | 2001-05-23 |
| GB2373855A true GB2373855A (en) | 2002-10-02 |
| GB2373855B GB2373855B (en) | 2005-08-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0107869A Expired - Fee Related GB2373855B (en) | 2001-03-29 | 2001-03-29 | A rapid method for estimation of chemical oxygen demand |
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| Country | Link |
|---|---|
| US (1) | US6967104B2 (en) |
| GB (1) | GB2373855B (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104820078A (en) * | 2014-01-30 | 2015-08-05 | 株式会社岛津制作所 | Detection method for multi-measuring range detection system, and multi-measuring range detection system |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101713739B (en) * | 2008-12-05 | 2012-07-04 | 江苏工业学院 | Reagent and method for determining chemical oxygen demand of high-chloride wastewater |
| CN101936977B (en) * | 2009-07-02 | 2012-01-25 | 杭州慕迪科技有限公司 | Method for recycling mixed reagent in COD (Chemical Oxygen Demand) online measuring process |
| CN102590464B (en) * | 2011-01-13 | 2014-10-01 | 中国石油化工股份有限公司 | Chemical oxygen demand determination method for water bodies |
| CN104020170A (en) * | 2014-06-12 | 2014-09-03 | 中国海洋石油总公司 | Method for determining chemical oxygen demand of high-chlorine waste water |
| TW202004169A (en) | 2018-06-04 | 2020-01-16 | 國立交通大學 | Color chart, test kit, and method for determining chemical oxygen demand of water and wastewater |
| CN112666158A (en) * | 2020-12-22 | 2021-04-16 | 南京启迪环保新能源有限公司 | Method capable of rapidly detecting COD concentration range of water body |
| CN113077019B (en) * | 2021-06-07 | 2021-09-17 | 芯视界（北京）科技有限公司 | Pollution type identification method and device and storage medium |
| CN113533235A (en) * | 2021-08-24 | 2021-10-22 | 郑州机械研究所有限公司 | Method for rapidly measuring silicon content in ferroalloy |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS5095176A (en) * | 1973-12-26 | 1975-07-29 | ||
| US5549789A (en) * | 1992-08-28 | 1996-08-27 | The United States Of America As Represented By The Secretary Of Agriculture | Oxidation of lignin and polysaccharides mediated by polyoxometalate treatment of wood pulp |
| DE10029146A1 (en) * | 1999-06-26 | 2000-12-28 | Merck Patent Gmbh | Recycling sulfuric acid solution containing metals, preferably test solutions from determination of chemical oxygen demand, involves redox-controlled separation of silver amalgam with iron and precipitation as hydroxide |
-
2001
- 2001-03-29 GB GB0107869A patent/GB2373855B/en not_active Expired - Fee Related
- 2001-03-29 US US09/820,538 patent/US6967104B2/en not_active Expired - Fee Related
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| Title |
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| Chemical Abstract No: 87:122365 & Ind. Aliment. 16(5), pages 109 - 112, 1977, * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104820078A (en) * | 2014-01-30 | 2015-08-05 | 株式会社岛津制作所 | Detection method for multi-measuring range detection system, and multi-measuring range detection system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2373855B (en) | 2005-08-10 |
| GB0107869D0 (en) | 2001-05-23 |
| US6967104B2 (en) | 2005-11-22 |
| US20030082817A1 (en) | 2003-05-01 |
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